STAT 121 Exam Commonly Tested Questions
Verified Answers
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?
,Producing Data
Big Picture of Statitics: 1 producing data, 2 exploratory data analysis, 3 probablity, 4 inference
True or False: Inference is the way that we are allowed to draw conclusions about
the population based on the data collected about the sample.
True
Administrators at Cosmo University are becoming more and more alarmed at the number of
hours students work per week. In order to examine the relationship between the number of
hours worked per week in a semester and that semester's GPA, one administrator surveyed
300 students currently attending the university. What type of variable is the number of
hours worked per week?what type of variable is GPA?
Quantitative
The number of hours worked per week is a quantitative variable (a variable with
meaningful numerical values).
Quantitative
GPA is a quantitative variable (a variable with meaningful numerical values).
A computer manufacturer has just received a shipment of 8000 computer chips. In order to
ensure that the shipment meets their quality standards, they want to sample a few chips and
make a detailed examination of the sample. The chips are packaged individually and have
serial numbers. If they use a statistical software package to randomly select serial numbers
for 20 chips for inspection, what type of sampling is this?
A simple random sample.
, This is a simple random sample because each chip has an equal probability of being selected,
it's like a draw from a hat. There is no grouping before we sampled so it's not a stratified
sample. We are randomly selecting our sample so it is not a convenience sample. And there are
not multiple levels of sampling so it is not a multistage sample.
True or False: Without random selection, we cannot appropriately apply the laws
of probability to perform inference.
True
The sample will only apply to the population that it represents. For example, if we took a
sample of students in just section 23 of stat 121, then our results would only represent that
section and not the whole class. However, if we took a random sample that included students
from all of the sections, this would represent the whole class.
The group we want to study or learn something about is known as the
population.
All statistics is about making inferences about our population. We do this by taking a sample
of individuals or groups to estimate what the population is like.
The college of humanities in a large university was accused of discrimination in their faculty
hiring. Twenty records of the recent female applicants who were not hired and twenty
records of recent male applicants who were not hired were randomly selected and
compared with the records of the recent hires. What type of sampling design is this?
A stratified sample.
This is a stratified sample because we are first spliting the population into two groups: male
and female. Then within each of those groups we take a sample and we compare the results.
They key part is that we split the population into groups then took samples
True or False: Convenience sampling is a type of probability sampling design.
Verified Answers
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?
,Producing Data
Big Picture of Statitics: 1 producing data, 2 exploratory data analysis, 3 probablity, 4 inference
True or False: Inference is the way that we are allowed to draw conclusions about
the population based on the data collected about the sample.
True
Administrators at Cosmo University are becoming more and more alarmed at the number of
hours students work per week. In order to examine the relationship between the number of
hours worked per week in a semester and that semester's GPA, one administrator surveyed
300 students currently attending the university. What type of variable is the number of
hours worked per week?what type of variable is GPA?
Quantitative
The number of hours worked per week is a quantitative variable (a variable with
meaningful numerical values).
Quantitative
GPA is a quantitative variable (a variable with meaningful numerical values).
A computer manufacturer has just received a shipment of 8000 computer chips. In order to
ensure that the shipment meets their quality standards, they want to sample a few chips and
make a detailed examination of the sample. The chips are packaged individually and have
serial numbers. If they use a statistical software package to randomly select serial numbers
for 20 chips for inspection, what type of sampling is this?
A simple random sample.
, This is a simple random sample because each chip has an equal probability of being selected,
it's like a draw from a hat. There is no grouping before we sampled so it's not a stratified
sample. We are randomly selecting our sample so it is not a convenience sample. And there are
not multiple levels of sampling so it is not a multistage sample.
True or False: Without random selection, we cannot appropriately apply the laws
of probability to perform inference.
True
The sample will only apply to the population that it represents. For example, if we took a
sample of students in just section 23 of stat 121, then our results would only represent that
section and not the whole class. However, if we took a random sample that included students
from all of the sections, this would represent the whole class.
The group we want to study or learn something about is known as the
population.
All statistics is about making inferences about our population. We do this by taking a sample
of individuals or groups to estimate what the population is like.
The college of humanities in a large university was accused of discrimination in their faculty
hiring. Twenty records of the recent female applicants who were not hired and twenty
records of recent male applicants who were not hired were randomly selected and
compared with the records of the recent hires. What type of sampling design is this?
A stratified sample.
This is a stratified sample because we are first spliting the population into two groups: male
and female. Then within each of those groups we take a sample and we compare the results.
They key part is that we split the population into groups then took samples
True or False: Convenience sampling is a type of probability sampling design.
