exam 1 stats review Questions with
complete solution 2025/2026
mutually exclusive - correct answer ✔Two events that cannot occur at the same time
2 branches of statistics - correct answer ✔descriptive and inferential
can you be exhaustive and mutually exclusive? - correct answer ✔Pass and fail are exhaustive and
mutually exclusive
The sum of probabilities of any list of mutually exclusive and exhaustive events equals 1.
how do you write the notation for 2 events that are independent - correct answer ✔Two events are
independent if the occurrence of one event does not affect the probability of the occurrence of another
event
Two events, A and B, are independent if
P(A|B) = P(A) or, equivalently
P(A^B) = P(A)P(B)
What is a z-score? - correct answer ✔number of standard deviations away from the mean
formula for z score - correct answer ✔x-xbar/sd
know how to calculate z score when given numbers - correct answer ✔If the distribution is relatively
symmetric and bell-shaped, use z-scores to detect outliers
Define population - correct answer ✔Population consists of all items/members of interest
, how is sample different from population - correct answer ✔Sample is a subset of population
Population: OU student body
Sample: Students in ECON 2843
quantitative variable - correct answer ✔A stem and leaf display is a way to present quantitative data in
a graphical format
qualitative variable - correct answer ✔A pie chart is a segmented circle whose segments portray the
relative frequencies of the categories of a qualitative variable
descriptive statistics - correct answer ✔Descriptive statistics refer to the summary of important aspects
of a data set
(collecting, organizing, and presenting data in the form of charts and tables)
Often calculate the average, median, mode, and variance
EX: the average test score on Test 1 was an 82%
inferential data - correct answer ✔Inferential statistics refers to drawing conclusions about a larger set
of data (population) based on a smaller set of data (sample)
A population consists of all items/members of interest
A sample is a subset of the population
Using the data to make predictions or conclusions from the data set
EX schools with universal free breakfast see a reduction in fights by 13.5% and Truancy by 22.1%
complete solution 2025/2026
mutually exclusive - correct answer ✔Two events that cannot occur at the same time
2 branches of statistics - correct answer ✔descriptive and inferential
can you be exhaustive and mutually exclusive? - correct answer ✔Pass and fail are exhaustive and
mutually exclusive
The sum of probabilities of any list of mutually exclusive and exhaustive events equals 1.
how do you write the notation for 2 events that are independent - correct answer ✔Two events are
independent if the occurrence of one event does not affect the probability of the occurrence of another
event
Two events, A and B, are independent if
P(A|B) = P(A) or, equivalently
P(A^B) = P(A)P(B)
What is a z-score? - correct answer ✔number of standard deviations away from the mean
formula for z score - correct answer ✔x-xbar/sd
know how to calculate z score when given numbers - correct answer ✔If the distribution is relatively
symmetric and bell-shaped, use z-scores to detect outliers
Define population - correct answer ✔Population consists of all items/members of interest
, how is sample different from population - correct answer ✔Sample is a subset of population
Population: OU student body
Sample: Students in ECON 2843
quantitative variable - correct answer ✔A stem and leaf display is a way to present quantitative data in
a graphical format
qualitative variable - correct answer ✔A pie chart is a segmented circle whose segments portray the
relative frequencies of the categories of a qualitative variable
descriptive statistics - correct answer ✔Descriptive statistics refer to the summary of important aspects
of a data set
(collecting, organizing, and presenting data in the form of charts and tables)
Often calculate the average, median, mode, and variance
EX: the average test score on Test 1 was an 82%
inferential data - correct answer ✔Inferential statistics refers to drawing conclusions about a larger set
of data (population) based on a smaller set of data (sample)
A population consists of all items/members of interest
A sample is a subset of the population
Using the data to make predictions or conclusions from the data set
EX schools with universal free breakfast see a reduction in fights by 13.5% and Truancy by 22.1%
