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

A pharmaceutical company wants to test a new drug. They randomly assign 200 patients to receive the drug and 200 to receive a placebo. Neither the patients nor the doctors know who receives which treatment. What type of experimental design is this?

Accepted Answer

Double-blind experiment

Question 3

Which sampling technique is used when a researcher divides a population into groups based on age and then randomly selects a sample from each age group?

Accepted Answer

Stratified sampling

Question 4

A city wants to know the exact number of residents living within its limits. Which method should they use?

Accepted Answer

Census

Question 5

What is the main purpose of using a control group in an experiment?

Accepted Answer

To keep all factors the same except for the treatment being tested

Question 6

A researcher stands outside a gym and surveys people as they leave about their exercise habits. What type of sampling is this?

Accepted Answer

Convenience sampling

Question 7

Which of the following is an example of a simulation in statistics?

Accepted Answer

Using a computer model to study the effects of car crashes

Question 8

A researcher wants to estimate the average number of hours students study per week. The true population average is 12 hours, but a random sample of 200 students yields an average of 10.8 hours. What is the sampling error?

Accepted Answer

$$12 - 10.8 = 1.2$$

Question 9

In a systematic sample, which of the following best describes the selection process?

Accepted Answer

Choose a starting value at random, then select every $$kth $$member.

Question 10

A researcher pairs up students with similar GPAs. One student in each pair receives a new study method, and the other uses the traditional method. What experimental design is this?

Accepted Answer

Matched-pairs design

Question 11

Which of the following is a confounding variable scenario?

Accepted Answer

A person starts a diet supplement and also begins exercising at the same time.

Question 12

Why is replication important in experimental design?

Accepted Answer

It allows researchers to confirm results and measure variation.

Question 13

A school randomly selects 5 classrooms and surveys all students in those classrooms. What sampling technique is this?

Accepted Answer

Cluster sampling

Question 14

Which of the following best describes the placebo effect?

Accepted Answer

Subjects react favorably to a fake treatment because they believe it is real.

Question 15

A company divides employees by department and randomly selects 10 employees from each department for a survey. What sampling technique is this?

Accepted Answer

Stratified sampling

Question 16

Which of the following is NOT a key element of a well-designed experiment?

Accepted Answer

Convenience

Question 17

A researcher assigns numbers to all students and uses a random number generator to select 100 students for a survey. What sampling technique is this?

Accepted Answer

Simple random sampling

Question 18

Which of the following scenarios best illustrates a biased sample?

Accepted Answer

Surveying only students in the library about study habits

Question 19

In a randomized block design, what is the main purpose of creating blocks?

Accepted Answer

To group subjects with similar characteristics before random assignment

Question 20

A quality control manager inspects every 20th product coming off the assembly line. What sampling technique is this?

Accepted Answer

Systematic sampling

Chapter 1: Data Collection and Experimental Design in Statistics

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