Question 1

Which of the following best describes a parameter in statistics?

Accepted Answer

A numerical summary describing a population.

Question 2

A researcher wants to study the average number of hours college students sleep per night. She randomly selects 200 students from a university and records their sleep hours. What type of variable is 'number of hours slept'?

Accepted Answer

Continuous variable

Question 3

Which level of measurement is appropriate for the variable 'temperature in degrees Celsius'?

Accepted Answer

Interval

Question 4

A pharmaceutical company conducts a study where some patients receive a new drug and others receive a placebo. Neither the patients nor the researchers know who receives which treatment. What type of experiment is this?

Accepted Answer

Double-blind experiment

Question 5

A survey is conducted by selecting every 10th person from a list of registered voters. What sampling method is being used?

Accepted Answer

Systematic sampling

Question 6

Which of the following is an example of a lurking variable in a study examining the relationship between exercise and weight loss?

Accepted Answer

Diet of the participants

Question 7

A researcher wants to compare the effectiveness of three teaching methods. She randomly assigns students to one of the three methods and measures their test scores. What is the response variable in this experiment?

Accepted Answer

Test score

Question 8

Which formula would you use to calculate the mean of a sample?

Accepted Answer

$$\displaystyle \bar{x} = \frac{\sum x_i}{n}$$

Question 9

A hospital wants to estimate the average recovery time for patients after surgery. They divide patients into groups based on age and randomly sample from each group. What sampling technique is this?

Accepted Answer

Stratified sampling

Question 10

Which of the following statements about observational studies is TRUE?

Accepted Answer

Researchers observe subjects without influencing them.

Question 11

A city government wants to estimate the proportion of residents who support a new park. They survey the first 200 people listed in the city’s phone directory. What type of bias is most likely present?

Accepted Answer

Sampling bias

Question 12

Which of the following is a quantitative variable?

Accepted Answer

Number of siblings

Question 13

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

Accepted Answer

To reduce the effects of confounding variables

Question 14

A study follows a group of smokers and non-smokers over 20 years to compare the incidence of lung cancer. What type of study is this?

Accepted Answer

Cohort (prospective) study

Question 15

Which formula represents the calculation of sample variance?

Accepted Answer

$$\displaystyle s^2$ = \frac{\sum (x_i - \bar{x})^2$}{n-1}$$

Question 16

A researcher interviews all passengers on three randomly selected flights. What sampling technique is being used?

Accepted Answer

Cluster sampling

Question 17

Which of the following is an example of a confounding variable in a study examining the effect of sleep on academic performance?

Accepted Answer

Study habits

Question 18

A sample is selected by asking people who happen to be passing by a shopping mall. What type of sampling is this?

Accepted Answer

Convenience sampling

Question 19

Which of the following best describes a case-control study?

Accepted Answer

Subjects with and without a condition are compared retrospectively.

Question 20

A researcher wants to design an experiment to test the effect of a new fertilizer on plant growth. Which of the following is the best way to ensure unbiased results?

Accepted Answer

Randomly assign plants to treatment and control groups.

Foundations of Statistics: Variables, Sampling, and Experimental Design

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