Question 1

Which of the following best defines statistics?

Accepted Answer

Statistics is the science of collecting, organizing, summarizing, analyzing, and making inferences from data.

Question 2

A researcher wants to study the effect of a new drug on blood pressure. She randomly assigns participants to either receive the drug or a placebo and measures their blood pressure after 6 weeks. What type of study is this?

Accepted Answer

A designed experiment

Question 3

Which of the following is a quantitative variable?

Accepted Answer

Number of siblings

Question 4

Suppose you record the number of students in each classroom at a university. What type of variable is this?

Accepted Answer

Quantitative and discrete

Question 5

Which of the following is an example of a parameter?

Accepted Answer

The proportion of all students at a university who own a car

Question 6

A researcher collects data on the number of hours students sleep per night and their GPA. Which is the explanatory variable?

Accepted Answer

Number of hours of sleep

Question 7

Which sampling method involves dividing the population into groups and randomly selecting all individuals from some of these groups?

Accepted Answer

Cluster sampling

Question 8

A survey asks respondents to rate their agreement with a statement on a scale from 1 (strongly disagree) to 5 (strongly agree). What is the level of measurement for this variable?

Accepted Answer

Ordinal

Question 9

Which of the following is an example of bias due to undercoverage?

Accepted Answer

A survey conducted by calling only landline phones, missing those who only use cell phones.

Question 10

In a systematic sample, if the population size is $$N = 1000$$ and the sample size is $$n = 50$$, what is the value of $$k ($$the sampling interval)?

Accepted Answer

$$k = 20$$

Question 11

Which of the following best describes a confounding variable?

Accepted Answer

A variable that is measured but not controlled in an experiment, potentially affecting the response variable.

Question 12

A researcher wants to compare the effectiveness of two teaching methods. She matches students based on their prior test scores and randomly assigns one from each pair to each method. What type of experimental design is this?

Accepted Answer

Matched-pairs design

Question 13

Which of the following variables is measured at the ratio level?

Accepted Answer

Number of books owned

Question 14

A study collects data on the brand of smartphone owned by students. What type of variable is this?

Accepted Answer

Qualitative, categorical

Question 15

Which of the following is an example of a cross-sectional study?

Accepted Answer

A study that surveys individuals about their exercise habits at one point in time.

Question 16

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

Accepted Answer

To group similar experimental units together to reduce variability.

Question 17

A researcher wants to estimate the average income of all households in a city. She divides the city into neighborhoods and randomly selects some neighborhoods, surveying all households in those neighborhoods. What sampling method is this?

Accepted Answer

Cluster sampling

Question 18

Which of the following is an example of response bias?

Accepted Answer

Survey respondents give answers they think are socially acceptable rather than truthful.

Question 19

Which of the following best describes a simple random sample?

Accepted Answer

Every individual in the population has an equal chance of being selected.

Question 20

A study records the time (in minutes) it takes for patients to recover after surgery. What is the level of measurement for this variable?

Accepted Answer

Ratio

Chapter 1: Data Collection – Foundations of Statistical Practice

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