Question 1

Which of the following best describes the difference between a population and a sample in statistics?

Accepted Answer

A population includes all possible data values for a group, while a sample is a subset of the population.

Question 2

Suppose you want to know the average commute time for all students at your university. You survey 200 randomly selected students. In this scenario, what is the population?

Accepted Answer

All students at your university.

Question 3

Which of the following variables is categorical?

Accepted Answer

Zip code

Question 4

A researcher records the number of doors on each car in a parking lot. What type of variable is 'number of doors'?

Accepted Answer

Numerical, because it describes a quantity.

Question 5

Which of the following is an example of a categorical variable that is disguised as numerical?

Accepted Answer

IsVehicle: 1 = Vehicle, 0 = Pedestrian.

Question 6

In a spreadsheet, each row contains data for a single individual and each column represents a variable. What is this data format called?

Accepted Answer

Stacked data

Question 7

Which of the following best describes unstacked data?

Accepted Answer

Each column is a variable from a different group, and info in a row does not correspond to the same individual.

Question 8

A researcher collects the following data: Make, Model, Head Injury (Yes/No), Number of Doors, and Weight. Which variables are numerical?

Accepted Answer

Number of Doors and Weight

Question 9

Suppose you have the following data table:

Men: 28, 29, 32, 34, 26
Women: 18, 23, 19, 36, 25

Is this data format stacked or unstacked?

Accepted Answer

Unstacked, because the columns represent two different groups.

Question 10

If you convert the above unstacked data to stacked format, which of the following best describes the new structure?

Accepted Answer

Each row contains the age and a coded gender variable (e.g., 1 for Men, 0 for Women).

Question 11

Which of the following is a correct way to code a categorical variable for analysis?

Accepted Answer

Assigning 1 to 'Yes' and 0 to 'No' for a variable like 'ActionTaken'.

Question 12

A student records the amount of sleep (in hours) for several nights and whether it was a weekend or weeknight. Which variable is categorical?

Accepted Answer

Weekend/Weeknight

Question 13

Which of the following best describes why it is important to keep an organized notebook of your homework in statistics?

Accepted Answer

It helps you to review and understand the material for tests and exams.

Question 14

Which of the following is NOT a recommended practice for success in this statistics course?

Accepted Answer

Relying on 'Help me solve this' for every homework problem.

Question 15

If you miss a test in this course, what is the policy for making it up?

Accepted Answer

You may replace the missed test with the final exam grade.

Question 16

Which of the following is a plausible reason why a variable coded as 0 or 1 might still be considered categorical?

Accepted Answer

Because arithmetic operations on the codes do not have meaningful interpretations.

Question 17

A researcher wants to compare the average test scores of students in two different classes. Which data format would be most appropriate for storing the scores?

Accepted Answer

Unstacked, with one column for each class.

Question 18

Which of the following best describes a variable?

Accepted Answer

A characteristic of people or things that can take on different values.

Question 19

Suppose you are analyzing the relationship between hours studied and exam scores. Which variable is numerical?

Accepted Answer

Hours studied

Understanding Stacked vs. Unstacked Data Formats in Introductory Statistics

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