DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Determine whether the given description corresponds to an experiment or an observational study. A stock analyst
selects a stock from a group of twenty for investment by choosing the stock with the greatest earnings per share
reported for the last quarter.
A) Experiment B) Observational study
Answer: B
2) Identify which type of sampling is used. The name of each contestant is written on a separate card, the cards are
placed in a bag, and three names are picked from the bag.
A) Cluster
B) Simple Random
C) Convenience
D) Systematic
E) Stratified
Answer: B
3) Identify which type of sampling is used. To avoid working late, a quality control analyst simply inspects the first
100 items produced in a day.
A) Cluster
B) Systematic
C) Simple Random
D) Stratified
E) Convenience
Answer: E
4) An education expert is researching teaching methods and wishes to interview teachers from a particular school
district. She randomly selects ten schools from the district and interviews all of the teachers at the selected schools.
Does this sampling plan result in a random sample? Simple random sample? Explain.
A) No; no. The sample is not random because teachers in small schools are more likely to be selected than
teachers in larger schools. It is not a simple random sample because some samples are not possible, such as a
sample that includes teachers from schools that were not selected.
B) Yes; yes. The sample is random because all teachers have the same chance of being selected. It is a simple
random sample because all samples have the same chance of being selected.
C) No; yes. The sample is not random because teachers in small schools are more likely to be selected than
teachers in larger schools. It is a simple random sample because all samples have the same chance of being
selected.
D) Yes; no. The sample is random because all teachers have the same chance of being selected. It is not a simple
random sample because some samples are not possible, such as a sample that includes teachers from schools
that were not selected.
Answer: D
5) Identify the type of observational study used. A town obtains current employment data by polling 10,000 of its
citizens this month.
A) Prospective B) Cross-sectional C) Retrospective D) None of these
Answer: B
1
mynursytest.store
,DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola
6) Determine whether the given value is a discrete or continuous variable. People are asked to state how many times 13) A psychology student wishes to investigate differences in political opinions between business majors and political
in the last month they visited their family doctor. science majors at her college. She randomly selects 100 students from the 260 business majors and 100 students
A) Discrete B) Continuous from the 180 political science majors. Does this sampling plan result in a random sample? Simple random sample?
Answer: A Explain.
A) Yes; no. The sample is random because all students have the same chance of being selected. It is not a simple
7) Determine which of the four levels of measurement is most appropriate. Students' grades, A, B, or C, on a test. random sample because some samples are not possible, such as a sample consisting of 50 business majors
A) Interval B) Ratio C) Ordinal D) Nominal and 150 political science majors.
B) No; yes. The sample is not random because political science majors have a greater chance of being selected
Answer: C
than business majors. It is a simple random sample because all samples of size 200 have the same chance of
being selected.
8) A tax auditor selects every 1000th income tax return that is received. Identify which of these types of sampling is
C) No; no. The sample is not random because political science majors have a greater chance of being selected
used.
than business majors. It is not a simple random sample because some samples are not possible, such as a
A) Systematic
sample consisting of 50 business majors and 150 political science majors.
B) Simple Random
D) Yes; yes. The sample is random because all students have the same chance of being selected. It is a simple
C) Convenience
random sample because all samples of size 200 have the same chance of being selected.
D) Stratified
E) Cluster Answer: C
Answer: A
14) Correlation does not imply ________.
A) linearity B) causation C) bias D) significance
9) Determine whether the given value is a statistic or a parameter. Thirty percent of all dog owners poop scoop after
their dog. Answer: B
A) Statistic B) Parameter
15) There are many potential pitfalls that can cause problems when analyzing data. Which of these choices are not
Answer: B
classified as a potential pitfall?
A) Nonresponse B) Self-reported data
10) Determine whether the given value is from a discrete or continuous data set. The time it takes a computer to
C) Order of survey questions D) Measured data
complete a task.
A) Discrete B) Continuous Answer: D
Answer: B
16) A management survey for a company surveyed 235 employees. 44.7% of the employees surveyed were females.
The number of males would be ________.
11) On a test, 74% of the questions are answered correctly. If 111 questions are correct, how many questions are on the
A) 13 B) 105
test?
C) 130 D) Unable to determine
A) 37 questions B) 67 questions C) 82 questions D) 150 questions
Answer: C
Answer: D
17) What type of data values are quantitative and the number of values is finite or countable?
12) Researchers collect data by interviewing athletes who have won Olympic gold medals from 1992 to 2016. Identify
A) Discrete B) Categorical C) Interval D) Continuous
the type of study.
A) Cross-sectional B) Retrospective C) Prospective D) None of these Answer: A
Answer: B
18) A ________ is the collection of data from every member of the population.
A) placebo B) statistic C) sample D) census
Answer: D
19) A ________ is the complete collection of all measurements or data collected, whereas, a ________ is a subcollection
of members selected from the complete collection.
A) sample; population B) population; parameter
C) sample; census D) population; sample
Answer: D
2 3
mynursytest.store mynursytest.store
,DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola
20) The four levels of measurement that are commonly used for classifying data are ratio, ________, ________, and 29) Identify which type of sampling is used. A research team wants to study the demographics of college students in
________. the United States using proportionate samples of students in majors reflecting actual U.S. percentages.
A) normal; ordinal; interval B) interval; normal; ordinary A) Convenience
C) nominal; ordinal; interval D) nominal; ordinal; categorical B) Cluster
Answer: C C) Systematic
D) Simple random
21) Identify which type of sampling is used. A pollster uses a computer to generate 500 random numbers, then E) Stratified
interviews the voters corresponding to those numbers. Answer: E
A) Random B) Systematic C) Stratified D) Convenience E) Cluster
Answer: A 30) A marijuana survey included 1610 responses from a list of approximately 241,500,000 adults in the United States
from which every 150,000th name was surveyed. Identify which of these types of sampling is used:
22) Determine whether the given value is a statistic or a parameter. After taking the first exam, 15 of the students A) Simple random
dropped the class. B) Convenience
A) Statistic B) Parameter C) Stratified
Answer: B D) Systematic
E) Cluster
23) Determine which of the four levels of measurement is most appropriate. Students' grades of A, B, or C, on a test. Answer: D
A) Ordinal B) Interval C) Ratio D) Nominal
Answer: A 31) A gardener has 75 clients, 45% of whom are businesses. Find the number of business clients.
A) 73 clients B) 36 clients C) 34 clients D) 41 clients
24) Determine which of the four levels of measurement is most appropriate. Level of satisfaction of survey Answer: C
respondents.
A) Interval B) Ratio C) Ordinal D) Nominal 32) A marketing firm does a survey to find out how many people use a product. Of the one hundred people contacted,
Answer: C fifteen said they use the product. Identify the type of study used.
A) Observational study B) Experiment
25) Identify which type of sampling is used. A tax auditor selects every 1000th income tax return that is received. Answer: A
A) Random B) Cluster C) Stratified D) Systematic E) Convenience
Answer: D 33) The similarity between an ordinal level of measurement and an interval level of measurement is that ________.
A) both can be arranged in some order
26) Determine whether the given description corresponds to an observational study or an experiment. A political B) neither can be arranged in some order
pollster reports that his candidate has a 10% lead in the polls with 10% undecided. C) differences between data values cannot be determined or are meaningless
A) Experiment B) Observational study D) differences between data values can be determined and are meaningful
Answer: B Answer: A
27) Identify the type of study used. A town obtains current employment data by polling 10,000 of its citizens this 34) Which of the following does not apply to the ratio level of measurement?
month. A) Differences between data values can be found and are meaningful
A) Prospective B) Cross-sectional C) Retrospective D) None of these B) Cannot be arranged in order
C) Can be arranged in order
Answer: B
D) There is a natural zero starting point
28) Determine whether the given description corresponds to an observational study or an experiment. A doctor gives a Answer: B
new medication to half of his patients with the flu and a placebo to the other half of his patients with the flu.
A) Experiment B) Observational study 35) Determine which level of measurement is appropriate. A sample of children's balls are classified from softest to
hardest.
Answer: A
A) Ordinal B) Interval C) Nominal D) Ratio
Answer: A
36) Determine which level of measurement is appropriate. Salaries of college professors.
A) Ratio B) Nominal C) Ordinal D) Interval
Answer: A
4 5
mynursytest.store mynursytest.store
, DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola
37) Which of the following is an inappropriate way to deal with missing data? 44) Subscribers of the women's magazine Cosmopolitan are asked to participate in a survey about preferred cereals for
A) Substitute missing values B) Determine if missing values are random breakfast. Are the results likely to be representative of all women? Of all subscribers of Cosmopolitan? Why or
C) Ignore missing data D) Delete cases with missing data why not?
Answer: C Answer: No. Cosmopolitan attracts women with specific demographics and subscribers will not be representative
of all women, however, a sample well selected, will not be representative. No, this sample will not even
38) In a cross-sectional study, data are ________. be representative of all Cosmopolitan subscribers because it is a voluntary response sample - subscribers
A) collected from a past time period themselves choose whether to respond. Those with stronger opinions are more likely to respond so the
B) observed, measured, and collected at one point of time sample is unlikely to be representative of all subscribers to the magazine.
C) collected in the future from groups that share common factors
D) observed, measure, and collected over a period of time 45) Given the data in the table, what issue can be addressed by conducting a statistical analysis of the values?
Answer: B
Amounts of Saturated Fat (in grams) in Two-Once Regular and Low-Fat Muffins
39) Which type of experiment separates subjects into groups that are similar but differ in ways that might affect the
outcome of the experiment? Regular 4.5 3.5 3.7 5.2 4.9 3.9
A) Randomized block design B) Rigorously controlled design Low-Fat 1.2 2.1 2.2 1.8 1.6 2.2
C) Matched pairs design D) Completely randomized design
Answer: A Answer: Given the context of the data, we could address the issue of whether the two types of muffins provide the
same amounts of saturated fat, or whether there is a difference between the two types of muffin.
40) The good design of experiments includes blinding, ________, and ________.
A) internalization; randomization B) replication; randomization 46) At a school there are two different math classes for children of the same age. The two classes have different
C) replication; voluntary response samples D) replication; experimentation teachers. The school principal is interested in gauging the effectiveness of two different teaching methods and asks
each teacher to try one of the methods. At the end of the semester both classes are given the same test and the
Answer: B
results are compared. In this experiment, what is the variable of interest? Give some examples of variables which
could be confounding variables.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
Answer: The variable of interest is the teaching method. Possible confounding variables are "skill of teacher" (is
41) Form a conclusion about statistical significance. Do not make any formal calculations. Either use the results one teacher better than the other?), "aptitude of students" (do the two classes have students of the same
provided or make subjective judgments about the results. ability?), "amount of study time" (does one class have students who are more conscientious?).
Last year, the average math SAT score for students at one school was 475. The headmaster introduced new
teaching methods hoping to improve scores. This year, the mean math SAT score for a sample of students was 481. 47) A lawyer surveyed a simple random sample of his colleagues and asked them whether they were left-handed or
Is there statistically significant evidence that the new teaching method is effective? If the teaching method had no right-handed. Is this convenience sample likely to provide results typical of all adults in the United States? Do
effect, there would be roughly a 3 in 10 chance of seeing such an increase. Does the result have statistical convenience samples in general provide good results?
significance? Why or why not? Does the result have practical significance? Answer: Yes. There is nothing about left-handedness or right-handedness that would affect being one of the
Answer: No. The new mean SAT score is not substantially higher. Even if the new teaching method had no effect, lawyer's colleagues. In terms of left- or right-handedness, a simple random sample of the lawyer's
a small increase such as this could easily be seen just by chance. No. The increase is not sufficient to be of colleagues is likely to be representative of all adults in the United States. Convenience samples in general
practical significance. do not tend to provide good results as the sample is often not representative of a broader population.
42) Why do you think that cluster sampling is frequently used in practice? 48) Identify the sample and population. Also, determine whether the sample is likely to be representative of the
Answer: Cluster sampling can save time and money and be more efficient, especially when the clusters are population. A study is interested in whether men and women are equally likely to vote Democratic, Republican or
geographically far apart from each other. If a study wants to solicit opinions from the homeless Independent or not vote in a presidential election. Results were polled through a popular news website.
population, it is more effective to choose a few selected towns and interview a significant number of Answer: Sample: the individuals who responded to the website poll; population: all voting age adults; not
homeless people in each town rather than study a few homeless people in all towns. A significant and representative due to being a convenience sample.
similar sample are identified in each cluster. In this case, a study accessing the entire population through
simple random sample would be too big and expensive. 49) Distinguish between categorical and quantitative data. Give an example of each.
In stratified sampling, the population is divided into strata according to some variables that are thought Answer: Qualitative data can be separated into categories that are distinguished by nonnumeric characteristics.
to be related to the variables of interest. A sample is taken from every stratum. There is not an identified Quantitative data consist of numbers representing counts or measurements. Examples will vary.
variable of interest in the homeless study.
50) Explain why using self-reported data instead of measured data is a potential pitfall in data collection. Be sure to
43) "38% of adults in the United States regularly visit a doctor". This conclusion was reached by a college student after include an example.
she had questioned 520 randomly selected members of her college. What is wrong with her conclusion?
Answer: Answers will vary. Using self-reported data may be inaccurate since people may want to represent
Answer: The sample is biased. College students are not representative of the U.S. population as a whole. themselves in a certain way. For example, people often report that they weigh less than they actually do.
6 7
mynursytest.store mynursytest.store
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Determine whether the given description corresponds to an experiment or an observational study. A stock analyst
selects a stock from a group of twenty for investment by choosing the stock with the greatest earnings per share
reported for the last quarter.
A) Experiment B) Observational study
Answer: B
2) Identify which type of sampling is used. The name of each contestant is written on a separate card, the cards are
placed in a bag, and three names are picked from the bag.
A) Cluster
B) Simple Random
C) Convenience
D) Systematic
E) Stratified
Answer: B
3) Identify which type of sampling is used. To avoid working late, a quality control analyst simply inspects the first
100 items produced in a day.
A) Cluster
B) Systematic
C) Simple Random
D) Stratified
E) Convenience
Answer: E
4) An education expert is researching teaching methods and wishes to interview teachers from a particular school
district. She randomly selects ten schools from the district and interviews all of the teachers at the selected schools.
Does this sampling plan result in a random sample? Simple random sample? Explain.
A) No; no. The sample is not random because teachers in small schools are more likely to be selected than
teachers in larger schools. It is not a simple random sample because some samples are not possible, such as a
sample that includes teachers from schools that were not selected.
B) Yes; yes. The sample is random because all teachers have the same chance of being selected. It is a simple
random sample because all samples have the same chance of being selected.
C) No; yes. The sample is not random because teachers in small schools are more likely to be selected than
teachers in larger schools. It is a simple random sample because all samples have the same chance of being
selected.
D) Yes; no. The sample is random because all teachers have the same chance of being selected. It is not a simple
random sample because some samples are not possible, such as a sample that includes teachers from schools
that were not selected.
Answer: D
5) Identify the type of observational study used. A town obtains current employment data by polling 10,000 of its
citizens this month.
A) Prospective B) Cross-sectional C) Retrospective D) None of these
Answer: B
1
mynursytest.store
,DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola
6) Determine whether the given value is a discrete or continuous variable. People are asked to state how many times 13) A psychology student wishes to investigate differences in political opinions between business majors and political
in the last month they visited their family doctor. science majors at her college. She randomly selects 100 students from the 260 business majors and 100 students
A) Discrete B) Continuous from the 180 political science majors. Does this sampling plan result in a random sample? Simple random sample?
Answer: A Explain.
A) Yes; no. The sample is random because all students have the same chance of being selected. It is not a simple
7) Determine which of the four levels of measurement is most appropriate. Students' grades, A, B, or C, on a test. random sample because some samples are not possible, such as a sample consisting of 50 business majors
A) Interval B) Ratio C) Ordinal D) Nominal and 150 political science majors.
B) No; yes. The sample is not random because political science majors have a greater chance of being selected
Answer: C
than business majors. It is a simple random sample because all samples of size 200 have the same chance of
being selected.
8) A tax auditor selects every 1000th income tax return that is received. Identify which of these types of sampling is
C) No; no. The sample is not random because political science majors have a greater chance of being selected
used.
than business majors. It is not a simple random sample because some samples are not possible, such as a
A) Systematic
sample consisting of 50 business majors and 150 political science majors.
B) Simple Random
D) Yes; yes. The sample is random because all students have the same chance of being selected. It is a simple
C) Convenience
random sample because all samples of size 200 have the same chance of being selected.
D) Stratified
E) Cluster Answer: C
Answer: A
14) Correlation does not imply ________.
A) linearity B) causation C) bias D) significance
9) Determine whether the given value is a statistic or a parameter. Thirty percent of all dog owners poop scoop after
their dog. Answer: B
A) Statistic B) Parameter
15) There are many potential pitfalls that can cause problems when analyzing data. Which of these choices are not
Answer: B
classified as a potential pitfall?
A) Nonresponse B) Self-reported data
10) Determine whether the given value is from a discrete or continuous data set. The time it takes a computer to
C) Order of survey questions D) Measured data
complete a task.
A) Discrete B) Continuous Answer: D
Answer: B
16) A management survey for a company surveyed 235 employees. 44.7% of the employees surveyed were females.
The number of males would be ________.
11) On a test, 74% of the questions are answered correctly. If 111 questions are correct, how many questions are on the
A) 13 B) 105
test?
C) 130 D) Unable to determine
A) 37 questions B) 67 questions C) 82 questions D) 150 questions
Answer: C
Answer: D
17) What type of data values are quantitative and the number of values is finite or countable?
12) Researchers collect data by interviewing athletes who have won Olympic gold medals from 1992 to 2016. Identify
A) Discrete B) Categorical C) Interval D) Continuous
the type of study.
A) Cross-sectional B) Retrospective C) Prospective D) None of these Answer: A
Answer: B
18) A ________ is the collection of data from every member of the population.
A) placebo B) statistic C) sample D) census
Answer: D
19) A ________ is the complete collection of all measurements or data collected, whereas, a ________ is a subcollection
of members selected from the complete collection.
A) sample; population B) population; parameter
C) sample; census D) population; sample
Answer: D
2 3
mynursytest.store mynursytest.store
,DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola
20) The four levels of measurement that are commonly used for classifying data are ratio, ________, ________, and 29) Identify which type of sampling is used. A research team wants to study the demographics of college students in
________. the United States using proportionate samples of students in majors reflecting actual U.S. percentages.
A) normal; ordinal; interval B) interval; normal; ordinary A) Convenience
C) nominal; ordinal; interval D) nominal; ordinal; categorical B) Cluster
Answer: C C) Systematic
D) Simple random
21) Identify which type of sampling is used. A pollster uses a computer to generate 500 random numbers, then E) Stratified
interviews the voters corresponding to those numbers. Answer: E
A) Random B) Systematic C) Stratified D) Convenience E) Cluster
Answer: A 30) A marijuana survey included 1610 responses from a list of approximately 241,500,000 adults in the United States
from which every 150,000th name was surveyed. Identify which of these types of sampling is used:
22) Determine whether the given value is a statistic or a parameter. After taking the first exam, 15 of the students A) Simple random
dropped the class. B) Convenience
A) Statistic B) Parameter C) Stratified
Answer: B D) Systematic
E) Cluster
23) Determine which of the four levels of measurement is most appropriate. Students' grades of A, B, or C, on a test. Answer: D
A) Ordinal B) Interval C) Ratio D) Nominal
Answer: A 31) A gardener has 75 clients, 45% of whom are businesses. Find the number of business clients.
A) 73 clients B) 36 clients C) 34 clients D) 41 clients
24) Determine which of the four levels of measurement is most appropriate. Level of satisfaction of survey Answer: C
respondents.
A) Interval B) Ratio C) Ordinal D) Nominal 32) A marketing firm does a survey to find out how many people use a product. Of the one hundred people contacted,
Answer: C fifteen said they use the product. Identify the type of study used.
A) Observational study B) Experiment
25) Identify which type of sampling is used. A tax auditor selects every 1000th income tax return that is received. Answer: A
A) Random B) Cluster C) Stratified D) Systematic E) Convenience
Answer: D 33) The similarity between an ordinal level of measurement and an interval level of measurement is that ________.
A) both can be arranged in some order
26) Determine whether the given description corresponds to an observational study or an experiment. A political B) neither can be arranged in some order
pollster reports that his candidate has a 10% lead in the polls with 10% undecided. C) differences between data values cannot be determined or are meaningless
A) Experiment B) Observational study D) differences between data values can be determined and are meaningful
Answer: B Answer: A
27) Identify the type of study used. A town obtains current employment data by polling 10,000 of its citizens this 34) Which of the following does not apply to the ratio level of measurement?
month. A) Differences between data values can be found and are meaningful
A) Prospective B) Cross-sectional C) Retrospective D) None of these B) Cannot be arranged in order
C) Can be arranged in order
Answer: B
D) There is a natural zero starting point
28) Determine whether the given description corresponds to an observational study or an experiment. A doctor gives a Answer: B
new medication to half of his patients with the flu and a placebo to the other half of his patients with the flu.
A) Experiment B) Observational study 35) Determine which level of measurement is appropriate. A sample of children's balls are classified from softest to
hardest.
Answer: A
A) Ordinal B) Interval C) Nominal D) Ratio
Answer: A
36) Determine which level of measurement is appropriate. Salaries of college professors.
A) Ratio B) Nominal C) Ordinal D) Interval
Answer: A
4 5
mynursytest.store mynursytest.store
, DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola DOWNLOAD THE Test Bank for Essentials of Statistics 7th Edition Triola
37) Which of the following is an inappropriate way to deal with missing data? 44) Subscribers of the women's magazine Cosmopolitan are asked to participate in a survey about preferred cereals for
A) Substitute missing values B) Determine if missing values are random breakfast. Are the results likely to be representative of all women? Of all subscribers of Cosmopolitan? Why or
C) Ignore missing data D) Delete cases with missing data why not?
Answer: C Answer: No. Cosmopolitan attracts women with specific demographics and subscribers will not be representative
of all women, however, a sample well selected, will not be representative. No, this sample will not even
38) In a cross-sectional study, data are ________. be representative of all Cosmopolitan subscribers because it is a voluntary response sample - subscribers
A) collected from a past time period themselves choose whether to respond. Those with stronger opinions are more likely to respond so the
B) observed, measured, and collected at one point of time sample is unlikely to be representative of all subscribers to the magazine.
C) collected in the future from groups that share common factors
D) observed, measure, and collected over a period of time 45) Given the data in the table, what issue can be addressed by conducting a statistical analysis of the values?
Answer: B
Amounts of Saturated Fat (in grams) in Two-Once Regular and Low-Fat Muffins
39) Which type of experiment separates subjects into groups that are similar but differ in ways that might affect the
outcome of the experiment? Regular 4.5 3.5 3.7 5.2 4.9 3.9
A) Randomized block design B) Rigorously controlled design Low-Fat 1.2 2.1 2.2 1.8 1.6 2.2
C) Matched pairs design D) Completely randomized design
Answer: A Answer: Given the context of the data, we could address the issue of whether the two types of muffins provide the
same amounts of saturated fat, or whether there is a difference between the two types of muffin.
40) The good design of experiments includes blinding, ________, and ________.
A) internalization; randomization B) replication; randomization 46) At a school there are two different math classes for children of the same age. The two classes have different
C) replication; voluntary response samples D) replication; experimentation teachers. The school principal is interested in gauging the effectiveness of two different teaching methods and asks
each teacher to try one of the methods. At the end of the semester both classes are given the same test and the
Answer: B
results are compared. In this experiment, what is the variable of interest? Give some examples of variables which
could be confounding variables.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
Answer: The variable of interest is the teaching method. Possible confounding variables are "skill of teacher" (is
41) Form a conclusion about statistical significance. Do not make any formal calculations. Either use the results one teacher better than the other?), "aptitude of students" (do the two classes have students of the same
provided or make subjective judgments about the results. ability?), "amount of study time" (does one class have students who are more conscientious?).
Last year, the average math SAT score for students at one school was 475. The headmaster introduced new
teaching methods hoping to improve scores. This year, the mean math SAT score for a sample of students was 481. 47) A lawyer surveyed a simple random sample of his colleagues and asked them whether they were left-handed or
Is there statistically significant evidence that the new teaching method is effective? If the teaching method had no right-handed. Is this convenience sample likely to provide results typical of all adults in the United States? Do
effect, there would be roughly a 3 in 10 chance of seeing such an increase. Does the result have statistical convenience samples in general provide good results?
significance? Why or why not? Does the result have practical significance? Answer: Yes. There is nothing about left-handedness or right-handedness that would affect being one of the
Answer: No. The new mean SAT score is not substantially higher. Even if the new teaching method had no effect, lawyer's colleagues. In terms of left- or right-handedness, a simple random sample of the lawyer's
a small increase such as this could easily be seen just by chance. No. The increase is not sufficient to be of colleagues is likely to be representative of all adults in the United States. Convenience samples in general
practical significance. do not tend to provide good results as the sample is often not representative of a broader population.
42) Why do you think that cluster sampling is frequently used in practice? 48) Identify the sample and population. Also, determine whether the sample is likely to be representative of the
Answer: Cluster sampling can save time and money and be more efficient, especially when the clusters are population. A study is interested in whether men and women are equally likely to vote Democratic, Republican or
geographically far apart from each other. If a study wants to solicit opinions from the homeless Independent or not vote in a presidential election. Results were polled through a popular news website.
population, it is more effective to choose a few selected towns and interview a significant number of Answer: Sample: the individuals who responded to the website poll; population: all voting age adults; not
homeless people in each town rather than study a few homeless people in all towns. A significant and representative due to being a convenience sample.
similar sample are identified in each cluster. In this case, a study accessing the entire population through
simple random sample would be too big and expensive. 49) Distinguish between categorical and quantitative data. Give an example of each.
In stratified sampling, the population is divided into strata according to some variables that are thought Answer: Qualitative data can be separated into categories that are distinguished by nonnumeric characteristics.
to be related to the variables of interest. A sample is taken from every stratum. There is not an identified Quantitative data consist of numbers representing counts or measurements. Examples will vary.
variable of interest in the homeless study.
50) Explain why using self-reported data instead of measured data is a potential pitfall in data collection. Be sure to
43) "38% of adults in the United States regularly visit a doctor". This conclusion was reached by a college student after include an example.
she had questioned 520 randomly selected members of her college. What is wrong with her conclusion?
Answer: Answers will vary. Using self-reported data may be inaccurate since people may want to represent
Answer: The sample is biased. College students are not representative of the U.S. population as a whole. themselves in a certain way. For example, people often report that they weigh less than they actually do.
6 7
mynursytest.store mynursytest.store
