Question 1

Which of the following best describes an observational study?

Accepted Answer

A researcher observes and measures characteristics of interest without influencing the subjects.

Question 2

In an experiment, what is the purpose of a placebo?

Accepted Answer

To act as a harmless, fake treatment that helps control for psychological effects.

Question 3

A coffee shop owner remodels her shop at the same time a nearby mall opens. Business increases, but it is unclear why. What statistical issue does this scenario illustrate?

Accepted Answer

Confounding variable

Question 4

Which technique is used to minimize the placebo effect in experiments?

Accepted Answer

Blinding

Question 5

In a double-blind experiment, who is unaware of which subjects receive the treatment?

Accepted Answer

Both the subjects and the experimenters

Question 6

A researcher divides subjects into age categories and then randomly assigns them to treatment or control groups within each category. What sampling design is this?

Accepted Answer

Randomized block design

Question 7

Why is replication important in experimental design?

Accepted Answer

It increases the validity of results by using a large group of subjects.

Question 8

Which sampling technique involves dividing a population into groups and selecting all members from one or more groups?

Accepted Answer

Cluster sampling

Question 9

A survey is conducted only on students in a biology class to determine opinions on stem cell research. What is the main issue with this sampling method?

Accepted Answer

It is a convenience sample and may be biased.

Question 10

Which of the following is a key element of a well-designed experiment?

Accepted Answer

Control

Question 11

A researcher wants to select a sample of 8 students from 731 enrolled in statistics by assigning numbers and using a random number table. What type of sampling is this?

Accepted Answer

Simple random sampling

Question 12

Which sampling technique involves choosing every $$k^{th}$$ member of the population after a random start?

Accepted Answer

Systematic sampling

Question 13

What is a sampling error?

Accepted Answer

The difference between the results of a sample and those of the population.

Question 14

In a matched-pairs design, how are subjects assigned treatments?

Accepted Answer

Subjects are paired by similarity, and one in each pair is randomly assigned a treatment.

Question 15

Which of the following is NOT a recommended sampling technique for statistical studies?

Accepted Answer

Convenience sampling

Question 16

A researcher uses a computer model to study the effects of car crashes on humans. What type of data collection is this?

Accepted Answer

Simulation

Question 17

Which of the following best describes a census?

Accepted Answer

A count or measure of an entire population.

Question 18

A company tests a new gum to help people quit smoking by giving it to five subjects and a placebo to five others. What is the main flaw in this experimental design?

Accepted Answer

Sample size is too small for valid results.

Question 19

Which step in designing a statistical study involves making decisions about the population using inferential statistics?

Accepted Answer

Interpret the data.

Question 20

A researcher divides students by major and randomly selects some from each major to survey. What sampling technique is this?

Accepted Answer

Stratified sampling

Data Collection and Experimental Design in Statistics

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