STAT 121 Exam need to Study Questions Verified
Answers
What are the 4 steps in the Big Picture? - ANS 1) Producing Data
2) Exploratory Data Analysis
3) Probability
4) Inference
What types of discipline is statistics? - ANS 1) art
2) science
3) methodology
What do statiticians do with data in the statistics process? - ANS 1) collect data
2) summarize data
3) interpret data
T or F: Gallop has never been wrong in predicting the winner of a presiential election? - ANS
False
When does the process of statistics start? - ANS When the group we want to study or learn
something about is identified
What is "Population" in statistics? - ANS the entire group of individuals
What is "sample" in statistics? - ANS a subgroup of the population that is being tested
What is meant by producing data? - ANS choosing a sample and collecting data from it
,Practice questions on pg. 10 in workbook - ANS
individual? - ANS entity observed
variable? - ANS characteristic or label (for values) that is measured for each individual
quantitative vs. categorical variables? - ANS Quantitative: meaningful numbers (have a value
attached)
Categorical: no value attached
measurement? - ANS value of a variable
T or F: Never take a quantitative variable and make it into a categorical variable? - ANS TRUE
What are the 2 parts of distribution of a variable? - ANS summary of data one variable at a time
1) all values of variable
2) how often occur
What does the distribution of textbook costs tell you?
a) who the students were
b) how the students were selected
c) that the costs were measured in dollars
d) how frequently the various costs occurred in the data set - ANS d) how frequently the various
costs occurred in the data set
,What are the components of an exploratory data analysis? - ANS -ORGANIZE and summarize
data
-DISCOVER: features, patterns, striking deviations from patterns
-INTERPRET patterns in context
-Single variable patterns (distribution) and 2 variable patterns (relationship)
-Visual displays and numerical summaries (communicates more info)
What is a definition ? - ANS a types of observational study in which individuals report variables'
values themselves, frequently by giving their opinions
What is purpose? - ANS sample fact in place of population fact (take what know about the
sample and determine the population)
What is the population in the potato example?
a) all potatoes in the world
b) all potatoes in the U.S.
c) all potatoes in the truckload
d) all potatoes in the buckets - ANS c) all potatoes in the truckload
What is the variable? - ANS characteristic that is measured
Parameter is related to what piece of information? What is statistic related to? - ANS Parameter
- population
Statistic - sample
What is the sampling method where you break the population into groups and get the sample
from each group (not randomized)? - ANS Quota Sampling
`
, What are the 3 bad ways of sampling? - ANS Quota sampling
Volunteer response sampling
Convenience sampling
To participate in the time.com poll go to the time website and click. What kind of sample is
time.com poll?
a) convenience
b) volunteer response
c) quota - ANS b) volunteer response
What is SRS? - ANS Simple Random Sample
What is the definition of SRS? - ANS Sample of specified size chosen such that every possible set
of that size has equal chance of being the sample
What is stratified random sampling? - ANS Quota samplind done right, because once you select
different groups, you randomize the samples in each group
What is a multistage sample? - ANS 1) SRS sample of state
2) SRS sample of counties in state
3) SRS farms in county
4) combined => 1 sample
The IRS obtains a sample of Utah tax returns by taking a random sample of Utah counties and
then taking a random sample of returns filed in those counties. What kind of sample is this?
a) SRS
b) Stratified random sample
c) multistage sample
Answers
What are the 4 steps in the Big Picture? - ANS 1) Producing Data
2) Exploratory Data Analysis
3) Probability
4) Inference
What types of discipline is statistics? - ANS 1) art
2) science
3) methodology
What do statiticians do with data in the statistics process? - ANS 1) collect data
2) summarize data
3) interpret data
T or F: Gallop has never been wrong in predicting the winner of a presiential election? - ANS
False
When does the process of statistics start? - ANS When the group we want to study or learn
something about is identified
What is "Population" in statistics? - ANS the entire group of individuals
What is "sample" in statistics? - ANS a subgroup of the population that is being tested
What is meant by producing data? - ANS choosing a sample and collecting data from it
,Practice questions on pg. 10 in workbook - ANS
individual? - ANS entity observed
variable? - ANS characteristic or label (for values) that is measured for each individual
quantitative vs. categorical variables? - ANS Quantitative: meaningful numbers (have a value
attached)
Categorical: no value attached
measurement? - ANS value of a variable
T or F: Never take a quantitative variable and make it into a categorical variable? - ANS TRUE
What are the 2 parts of distribution of a variable? - ANS summary of data one variable at a time
1) all values of variable
2) how often occur
What does the distribution of textbook costs tell you?
a) who the students were
b) how the students were selected
c) that the costs were measured in dollars
d) how frequently the various costs occurred in the data set - ANS d) how frequently the various
costs occurred in the data set
,What are the components of an exploratory data analysis? - ANS -ORGANIZE and summarize
data
-DISCOVER: features, patterns, striking deviations from patterns
-INTERPRET patterns in context
-Single variable patterns (distribution) and 2 variable patterns (relationship)
-Visual displays and numerical summaries (communicates more info)
What is a definition ? - ANS a types of observational study in which individuals report variables'
values themselves, frequently by giving their opinions
What is purpose? - ANS sample fact in place of population fact (take what know about the
sample and determine the population)
What is the population in the potato example?
a) all potatoes in the world
b) all potatoes in the U.S.
c) all potatoes in the truckload
d) all potatoes in the buckets - ANS c) all potatoes in the truckload
What is the variable? - ANS characteristic that is measured
Parameter is related to what piece of information? What is statistic related to? - ANS Parameter
- population
Statistic - sample
What is the sampling method where you break the population into groups and get the sample
from each group (not randomized)? - ANS Quota Sampling
`
, What are the 3 bad ways of sampling? - ANS Quota sampling
Volunteer response sampling
Convenience sampling
To participate in the time.com poll go to the time website and click. What kind of sample is
time.com poll?
a) convenience
b) volunteer response
c) quota - ANS b) volunteer response
What is SRS? - ANS Simple Random Sample
What is the definition of SRS? - ANS Sample of specified size chosen such that every possible set
of that size has equal chance of being the sample
What is stratified random sampling? - ANS Quota samplind done right, because once you select
different groups, you randomize the samples in each group
What is a multistage sample? - ANS 1) SRS sample of state
2) SRS sample of counties in state
3) SRS farms in county
4) combined => 1 sample
The IRS obtains a sample of Utah tax returns by taking a random sample of Utah counties and
then taking a random sample of returns filed in those counties. What kind of sample is this?
a) SRS
b) Stratified random sample
c) multistage sample
