Question 1

Which of the following best describes the difference between a population and a sample in statistics?

Accepted Answer

A population includes all subjects of interest, while a sample is a subset of the population.

Question 2

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

Accepted Answer

Experiment

Question 3

Which of the following is a key advantage of an experiment over an observational study?

Accepted Answer

Experiments can establish cause and effect relationships.

Question 4

In a study on alcohol consumption and type II diabetes, researchers observed participants’ drinking habits and diabetes status without assigning treatments. What is a major limitation of this study design?

Accepted Answer

It cannot establish causation due to possible lurking variables.

Question 5

Which of the following best defines a simple random sample (SRS)?

Accepted Answer

A sample where each possible sample of the same size has the same chance of being selected.

Question 6

A survey reports a margin of error of $$\pm 4\%. If $$the sample percentage is $$60\%$$, what is the likely range for the population percentage?

Accepted Answer

$$56\% to$$ $$64\%$$

Question 7

Which of the following is an example of a convenience sample?

Accepted Answer

Surveying people at a shopping mall about city-wide opinions.

Question 8

What type of bias occurs when some sampled subjects cannot be reached or refuse to participate?

Accepted Answer

Nonresponse bias

Question 9

In an experiment, what is the purpose of randomization?

Accepted Answer

To eliminate researcher bias and balance groups on known and unknown variables.

Question 10

A double-blinded experiment is one in which:

Accepted Answer

Neither the subjects nor the investigators know which treatment each subject receives.

Question 11

Which of the following is NOT a component of a good experiment?

Accepted Answer

Convenience sampling

Question 12

A placebo effect in a clinical trial refers to:

Accepted Answer

An improvement in health due to the patient’s belief in the treatment, not the treatment itself.

Question 13

Which of the following best describes statistical significance?

Accepted Answer

A result that is larger than what would be expected by chance alone.

Question 14

Why should results of a study only be generalized to the population represented by the study?

Accepted Answer

Because practical constraints may limit the realism of the study.

Question 15

Which of the following is an example of response bias?

Accepted Answer

Subjects give answers they think are expected rather than their true beliefs.

Question 16

A researcher wants to estimate the percentage of students who prefer online classes. She selects 100 students using a random number generator from the college’s enrollment list. What is the sampling frame in this scenario?

Accepted Answer

The college’s enrollment list.

Question 17

If a sample survey uses a simple random sample of $$n$$ subjects, the margin of error is approximately:

Accepted Answer

$$\frac{1}{\sqrt{n}}$$

Question 18

In a multifactor experiment, what is a treatment?

Accepted Answer

A specific combination of values of the explanatory variables assigned to subjects.

Question 19

Which of the following is a real-world example of undercoverage bias?

Accepted Answer

Surveying only landline phone users about internet habits.

Question 20

Why is replication important in experimental design?

Accepted Answer

It increases the likelihood that observed effects are due to treatments rather than chance.

Lesson 2

Study Guide - Practice Questions

Study Guide - Flashcards