Question 1

Which of the following best describes the main difference between descriptive statistics and inferential statistics?

Accepted Answer

Descriptive statistics summarize and organize data, while inferential statistics use sample data to draw conclusions about a population.

Question 2

A researcher wants to know if a new teaching method improves student performance. She randomly assigns students to two groups: one uses the new method, the other uses the traditional method. At the end of the semester, she compares their test scores. What type of study is this?

Accepted Answer

Designed experiment

Question 3

Which of the following variables is discrete?

Accepted Answer

The number of cars sold at a dealership in a day

Question 4

A study collects the average cholesterol level of 100 randomly selected adults in a city. The average is used to estimate the cholesterol level of all adults in the city. In this context, what is the sample?

Accepted Answer

The 100 randomly selected adults

Question 5

Which of the following is an example of a qualitative variable?

Accepted Answer

Favorite color

Question 6

A hospital administrator wants to estimate the average waiting time in the emergency room. She records the waiting times of every 5th patient who arrives during a week. What sampling method is being used?

Accepted Answer

Systematic sampling

Question 7

Which of the following best describes a cluster sample?

Accepted Answer

Randomly selecting entire groups from the population and including all individuals in those groups in the sample

Question 8

A study finds that 44% of surveyed adults support a new policy. This value is best described as:

Accepted Answer

A statistic

Question 9

Which of the following statements about observational studies is TRUE?

Accepted Answer

Observational studies can identify associations but not causation.

Question 10

A researcher divides a population of students into males and females, then randomly selects 20 males and 20 females to participate in a survey. What type of sampling is this?

Accepted Answer

Stratified sampling

Question 11

Which of the following is an example of a continuous variable?

Accepted Answer

Amount of rainfall in a month (in millimeters)

Question 12

A study selects a group of people with skin cancer and a group without skin cancer, then asks both groups about their past use of tanning beds. What type of study is this?

Accepted Answer

Case-control study

Question 13

Which of the following best describes a simple random sample?

Accepted Answer

Every individual in the population has an equal chance of being selected.

Question 14

A researcher wants to study the effect of caffeine on memory. She gives one group of participants caffeine and another group a placebo, then measures their memory performance. What is the explanatory variable in this study?

Accepted Answer

Amount of caffeine consumed

Question 15

Which of the following is a key characteristic of a cohort study?

Accepted Answer

It follows a group of individuals over time to observe outcomes.

Question 16

Suppose you want to select a simple random sample of 5 students from a class of 30. Which of the following procedures would ensure a simple random sample?

Accepted Answer

Assign each student a number from 1 to 30 and use a random number generator to select 5 unique numbers.

Question 17

A study records the number of children in each household in a city. What type of variable is 'number of children'?

Accepted Answer

Quantitative and discrete

Question 18

Which of the following best describes a cross-sectional study?

Accepted Answer

It collects data from participants at a single point in time.

Question 19

In the four-step statistical process, which step involves interpreting findings and relating them to the original question?

Accepted Answer

Conclusion (Interpret the Results)

Question 20

A researcher wants to study the effect of a new drug on blood pressure. She randomly assigns 100 patients to receive either the new drug or a placebo, then measures their blood pressure after 6 weeks. Which of the following best describes the study design?

Accepted Answer

Designed experiment

Introduction to the Practice of Statistics: Key Concepts, Data Types, Study Designs, and Sampling Methods

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