STAT 121 Exam Commonly Tested Questions Verified
Answers
What is the final step in the Big Picture of statistics, as outlined in class?
Inference
The four steps in the Big Picture of statistics are:
1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
True or False: All statistical summaries and conclusions should be reported in context.
True
If statisical results were reported out of context what would they tell us? We need to report
them in context to be able to understand the data.
What does the statistical term "population" refer to?
It refers to the group we want to study or learn something about.
CMU eBook page 5 says: "The process of statistics starts when we identify what group we want
to study or learn something about. We call this group the population."
What is the purpose of statistics?
To convert data into useful information.
CMU eBook page 5: "what statistics is all about is converting data into useful information."
,A study of religious practices among college students interviewed a sample of 127 students;
107 of the students said that they prayed at least once in a while. Which of the following best
describes the sample?
The 127 college students who were interviewed.
We're studying the religious practices among all college students, not just those who are
already doing religious practices.
A sample of 12th-grade students who took the National Assessment of Education Progress
year 2000 mathematics test had a mean score of 250.
Referring to the previous question, the variable test scores is quantitative. (t/f?)
What is the population?
True
all 12th-grade students who took the National Assessment of Educational Progress year 2000
mathematics test
The purpose of this study was to determine the effect of adding a unit to the district's math
course would have on the scores of the state exam. This study was done with a sample of ninth-
grade students who were enrolled in a general mathematics course.
Why might collecting data from a sample be preferred over collecting data from a
population?
A. Less expensive.
B. Less time consuming.
C. Collecting data from the entire population may be impossible.
D. All of the above.
,D. All of the above.
CMU eBook page 5 says: "In most cases the population is so large that as much as we want to,
there is absolutely no way we can study all of it. A more practical approach would be to
examine and collect data from a sub-group of the population, which we call a sample."
Which of the following is not part of the Big Picture of Statistics?
A. Collecting data.
B. Summarizing data.
C. Interpreting data.
D. Publishing research results.
D. Publishing research results.
We're never required to publish our results to the public.
Which of the following is a categorical variable?
A. Height
B. Phone Number
C. Mile time
D. Book costs
B. Phone Number
Statistics is a process where we do which of the following?
A. Collect data
B. Summarize data
C. Interpret data
D. All of the above
D. All of the above
Big Picture of Statistics: 1 producing data, 2 exploratory data analysis, 3 probability, 4 inference
, True or False: The Field of Statistics starts when we begin summarizing data.
False
Big Picture of Statistics: 1 producing data, 2 exploratory data analysis, 3 probablity, 4 inference
True or False: The statistical term population can only refer to people.
False
The population is the group we are interested in.
What is a sample?
It is a subgroup of the population.
Definition of a sample
We sometimes hear that marriage is good for your career. A sample of 8235 managers and
professionals employed by a specific large manufacturing firm were asked their marital status
(married, single, widowed, or divorced) and their annual income. The mean annual income
was then calculated for each of the four marital status groups. What is the population? what
is the sample?
All managers and professionals employed by this manufacturing firm.
Our sample comes from our population so if the sample was taken from managers and
professionals employed by a specific large manufacturing firm, then that will be our population.
The 8235 managers and professionals from this large manufacturing firm.
What is the first step in the Big Picture of Statistics?
Answers
What is the final step in the Big Picture of statistics, as outlined in class?
Inference
The four steps in the Big Picture of statistics are:
1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
True or False: All statistical summaries and conclusions should be reported in context.
True
If statisical results were reported out of context what would they tell us? We need to report
them in context to be able to understand the data.
What does the statistical term "population" refer to?
It refers to the group we want to study or learn something about.
CMU eBook page 5 says: "The process of statistics starts when we identify what group we want
to study or learn something about. We call this group the population."
What is the purpose of statistics?
To convert data into useful information.
CMU eBook page 5: "what statistics is all about is converting data into useful information."
,A study of religious practices among college students interviewed a sample of 127 students;
107 of the students said that they prayed at least once in a while. Which of the following best
describes the sample?
The 127 college students who were interviewed.
We're studying the religious practices among all college students, not just those who are
already doing religious practices.
A sample of 12th-grade students who took the National Assessment of Education Progress
year 2000 mathematics test had a mean score of 250.
Referring to the previous question, the variable test scores is quantitative. (t/f?)
What is the population?
True
all 12th-grade students who took the National Assessment of Educational Progress year 2000
mathematics test
The purpose of this study was to determine the effect of adding a unit to the district's math
course would have on the scores of the state exam. This study was done with a sample of ninth-
grade students who were enrolled in a general mathematics course.
Why might collecting data from a sample be preferred over collecting data from a
population?
A. Less expensive.
B. Less time consuming.
C. Collecting data from the entire population may be impossible.
D. All of the above.
,D. All of the above.
CMU eBook page 5 says: "In most cases the population is so large that as much as we want to,
there is absolutely no way we can study all of it. A more practical approach would be to
examine and collect data from a sub-group of the population, which we call a sample."
Which of the following is not part of the Big Picture of Statistics?
A. Collecting data.
B. Summarizing data.
C. Interpreting data.
D. Publishing research results.
D. Publishing research results.
We're never required to publish our results to the public.
Which of the following is a categorical variable?
A. Height
B. Phone Number
C. Mile time
D. Book costs
B. Phone Number
Statistics is a process where we do which of the following?
A. Collect data
B. Summarize data
C. Interpret data
D. All of the above
D. All of the above
Big Picture of Statistics: 1 producing data, 2 exploratory data analysis, 3 probability, 4 inference
, True or False: The Field of Statistics starts when we begin summarizing data.
False
Big Picture of Statistics: 1 producing data, 2 exploratory data analysis, 3 probablity, 4 inference
True or False: The statistical term population can only refer to people.
False
The population is the group we are interested in.
What is a sample?
It is a subgroup of the population.
Definition of a sample
We sometimes hear that marriage is good for your career. A sample of 8235 managers and
professionals employed by a specific large manufacturing firm were asked their marital status
(married, single, widowed, or divorced) and their annual income. The mean annual income
was then calculated for each of the four marital status groups. What is the population? what
is the sample?
All managers and professionals employed by this manufacturing firm.
Our sample comes from our population so if the sample was taken from managers and
professionals employed by a specific large manufacturing firm, then that will be our population.
The 8235 managers and professionals from this large manufacturing firm.
What is the first step in the Big Picture of Statistics?
