Question 1

Which of the following best describes the main goal of statistics?

Accepted Answer

To describe and understand sources of variability in data.

Question 2

A researcher wants to know if a new teaching method improves math scores. She randomly assigns students to either the new method or the traditional method and compares their final exam scores. What type of study is this?

Accepted Answer

Designed experiment

Question 3

Which of the following is an example of a quantitative variable?

Accepted Answer

Number of vending machines at a school

Question 4

Suppose a researcher collects the daily intake of whole grains (measured in grams per day) from a sample of students. What type of variable is this, and is it discrete or continuous?

Accepted Answer

Quantitative, continuous

Question 5

Which of the following best defines a parameter?

Accepted Answer

A numerical summary of a population

Question 6

A study finds that students who start school at 8:30 am or later sleep an average of 27.5 minutes longer than those who start earlier. Which step of the statistical process does this represent?

Accepted Answer

Drawing conclusions from the data

Question 7

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

Accepted Answer

Gender

Question 8

A researcher wants to estimate the average number of hours college students study per week. She selects 100 students at random from the university. What is the population in this study?

Accepted Answer

All college students at the university

Question 9

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

Accepted Answer

Cluster sampling

Question 10

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

Accepted Answer

Dietary habits not measured in the study

Question 11

A variable is measured at the interval level if:

Accepted Answer

It has properties of the nominal and ordinal levels, and differences between values are meaningful, but there is no true zero

Question 12

Which of the following best describes a discrete variable?

Accepted Answer

A variable that can only take on a finite or countable number of values

Question 13

A researcher records the number of children in each classroom in a school. What type of variable is this?

Accepted Answer

Quantitative, discrete

Question 14

Which of the following is an example of data measured at the ratio level?

Accepted Answer

Number of days per week a student eats lunch

Question 15

In a study, the researcher observes whether students are prepared for class without intervening. What type of study is this?

Accepted Answer

Observational study

Question 16

Which of the following best describes confounding in a study?

Accepted Answer

When the effects of two or more explanatory variables are not separated

Question 17

A researcher wants to compare the average test scores of students from different income statuses (low, middle, high). What is the level of measurement for income status?

Accepted Answer

Ordinal

Question 18

Which of the following is an example of a qualitative variable?

Accepted Answer

Name of a university

Question 19

A sample is best defined as:

Accepted Answer

A subset of the population being studied

Question 20

Which of the following is an example of a variable measured at the ordinal level?

Accepted Answer

Income status (low, middle, high)

Introduction to the Practice of Statistics: Key Concepts and Methods

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