Question 1

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

Accepted Answer

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

Question 2

A researcher wants to study the effect of a new drug on blood pressure. She randomly assigns participants to receive either the drug or a placebo and measures their blood pressure after 8 weeks. What type of study is this?

Accepted Answer

Designed experiment

Question 3

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

Accepted Answer

The number of cars owned by a family

Question 4

A simple random sample of size $$n$$ from a population of size $$N is $$defined as:

Accepted Answer

A sample in which every possible sample of size $$n$$ has an equal chance of occurring.

Question 5

In a study, researchers record the number of children in a household. This variable is:

Accepted Answer

Quantitative and discrete

Question 6

Which sampling technique involves dividing the population into homogeneous groups and then randomly sampling from each group?

Accepted Answer

Stratified sampling

Question 7

A researcher wants to study the relationship between coffee consumption and skin cancer. She selects a group of people with skin cancer and a group without, then asks about their coffee habits. What type of study is this?

Accepted Answer

Case-control study

Question 8

Which of the following is a continuous variable?

Accepted Answer

Daily intake of whole grains (measured in grams per day)

Question 9

In a systematic sample, if the population size is $$N = 100$$ and the sample size is $$n = 10$$, what is the value of $$k ($$the interval for selection)?

Accepted Answer

$$k = 10$$

Question 10

Which statement about observational studies is TRUE?

Accepted Answer

Observational studies only allow researchers to claim association, not causation.

Question 11

A researcher wants to select every 5th person from a list of 200 students. What sampling method is being used?

Accepted Answer

Systematic sampling

Question 12

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

Accepted Answer

Type of car owned

Question 13

In a cohort study, what is the main characteristic that distinguishes it from other observational studies?

Accepted Answer

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

Question 14

A researcher wants to study the effect of exercise on cholesterol levels. She collects data from participants at one point in time. What type of observational study is this?

Accepted Answer

Cross-sectional study

Question 15

Which of the following best describes a cluster sample?

Accepted Answer

A sample obtained by randomly selecting entire groups from the population.

Question 16

In a designed experiment, what is the purpose of random assignment?

Accepted Answer

To eliminate bias and confounding variables by evenly distributing them across treatment groups.

Question 17

A study records the average score for a class of 28 students taking a calculus midterm exam. The average score is considered a:

Accepted Answer

Statistic

Question 18

Which of the following is a lurking variable in a study examining the relationship between exercise and heart disease?

Accepted Answer

Dietary habits

Question 19

A researcher uses a random number generator to select 10 students from a list of 100. What sampling method is this?

Accepted Answer

Simple random sampling

Question 20

Which of the following statements about variables is correct?

Accepted Answer

A discrete variable has a countable number of possible values.

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

Guida di studio - Domande di pratica

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