Question 1

Which of the following best describes an observational study?

Accepted Answer

A researcher observes and measures characteristics of a sample without changing existing conditions.

Question 2

A pharmaceutical company wants to test a new drug. They randomly assign 500 patients to receive the drug and 500 to receive a placebo. Neither the patients nor the doctors know who receives the drug. What type of experimental design is this?

Accepted Answer

Double-blind experiment

Question 3

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 on passengers

Question 4

A researcher divides a population of households into socioeconomic levels and randomly selects households from each level. What sampling technique is being used?

Accepted Answer

Stratified sampling

Question 5

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

Accepted Answer

All of the above

Question 6

A coffee shop remodels and a new mall opens nearby. Business increases, but the owner cannot tell which change caused the increase. This is an example of:

Accepted Answer

Confounding variables

Question 7

Which of the following best describes a simple random sample?

Accepted Answer

Every possible sample of the same size has the same chance of being selected.

Question 8

A researcher selects every 10th person from a list of 1000 employees. What sampling technique is this?

Accepted Answer

Systematic sampling

Question 9

Why is replication important in experimental design?

Accepted Answer

It increases the validity of the results by repeating the experiment under similar conditions.

Question 10

A survey is conducted by interviewing only students in the library. What type of sampling is this, and what is a likely problem?

Accepted Answer

Convenience sampling; the sample may be biased.

Question 11

Which of the following best describes the placebo effect?

Accepted Answer

Subjects react favorably to a fake treatment.

Question 12

A company tests a new product by giving it to 5 people and a placebo to another 5 people. What is the main problem with this experimental design?

Accepted Answer

The sample size is too small to validate the results.

Question 13

Which of the following is NOT a recommended method for collecting data in a statistical study?

Accepted Answer

Convenience sampling

Question 14

A researcher divides subjects into age groups, then randomly assigns subjects within each group to treatment or control. What design is this?

Accepted Answer

Randomized block design

Question 15

Which of the following equations represents the probability of selecting a specific member in a simple random sample of size $$n$$ from a population of size $$N$$?

Accepted Answer

$$P = \frac{1}{N}$$

Question 16

Which of the following best describes a cluster sample?

Accepted Answer

Divide the population into groups and select all members from some groups.

Question 17

A researcher wants to study the effect of a new teaching method. She pairs students based on their previous test scores, then randomly assigns one in each pair to the new method and the other to the traditional method. What design is this?

Accepted Answer

Matched-pairs design

Question 18

Which of the following is a potential source of bias in survey design?

Accepted Answer

Wording questions to lead to a particular answer

Question 19

A census is different from a sample in that:

Accepted Answer

A census measures the entire population.

Question 20

Which of the following is an example of a sampling error?

Accepted Answer

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

Chapter 1: Data Collection and Experimental Design – Study Notes

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