Question 1

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

Accepted Answer

A sample is a subset of the population from which data are obtained, while a population is the complete set of people or objects being studied.

Question 2

A researcher collects data on the number of calories in sandwiches sold at a restaurant. Which type of variable is 'number of calories'?

Accepted Answer

Numerical (quantitative) variable

Question 3

Which of the following is an example of a confounding variable in a study examining the effect of exercise on weight loss?

Accepted Answer

The participants' initial weight

Question 4

A study finds that children with larger shoe sizes tend to have higher vocabulary scores. What is the most likely explanation for this association?

Accepted Answer

Both shoe size and vocabulary are associated with age, which is a confounding variable.

Question 5

In a controlled experiment, why is random assignment of subjects to treatment and control groups important?

Accepted Answer

It minimizes bias and helps ensure that differences between groups are due to the treatment.

Question 6

A survey asks students to indicate their housing situation (Dorm, Apartment, Parents). What type of variable is 'housing situation'?

Accepted Answer

Categorical variable

Question 7

A frequency table is used to:

Accepted Answer

Show the totals and use category names to label each row.

Question 8

If 400 students are surveyed and 65% are carrying calculators, how many students are carrying calculators?

Accepted Answer

$$400 	imes 0.65 = 260$$

Question 9

Why are rates (such as 'injuries per 1,000 people') often more useful than counts when comparing groups?

Accepted Answer

Rates account for differences in group sizes, allowing fair comparisons.

Question 10

Which of the following best describes a double-blind study?

Accepted Answer

Both the participants and the researchers do not know who is in the treatment or control group.

Question 11

A study reports that children whose mothers chose to take high doses of vitamin C had a 30% lower risk of developing allergies. Why can we NOT conclude that vitamin C causes a reduction in allergies?

Accepted Answer

Because the researchers did not randomly assign mothers to treatment and control groups.

Question 12

Which of the following is an example of coding a categorical variable with numbers?

Accepted Answer

Assigning 1 for 'Yes' and 0 for 'No' in a survey question.

Question 13

In a study, 50 mice are randomly assigned to two groups: one group receives 12 hours of light and 12 hours of dark (LD), and the other receives 24 hours of light (LL). What type of study is this?

Accepted Answer

Controlled experiment

Question 14

Which of the following is NOT a 'W' used to provide context for data?

Accepted Answer

Which

Question 15

A two-way table is most useful for:

Accepted Answer

Showing the relationship between two categorical variables.

Question 16

A placebo effect occurs when:

Accepted Answer

A participant reacts to a fake treatment because they believe it is real.

Question 17

Which of the following statements about association and causation is correct?

Accepted Answer

Association does not necessarily mean causation.

Question 18

A study compares the effectiveness of three treatments for a disease. The remission rates are: Combination (56.8%), Inflix alone (44.4%), Azath alone (30%). What is the most effective treatment for this sample?

Accepted Answer

Combination

Question 19

If a researcher assigns the heaviest people to the exercise group in a weight loss study, what type of bias is introduced?

Accepted Answer

Selection bias

Introduction to Data: Foundations of Statistics (Chapter 1 Study Notes)

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