Question 1

Which of the following best describes a quantitative variable?

Accepted Answer

A variable that provides a numerical measure of an individual, such as height or weight.

Question 2

In a study examining the effect of a new medication on blood pressure, which is the explanatory variable?

Accepted Answer

The new medication

Question 3

Which of the following is an example of a designed experiment?

Accepted Answer

Researchers randomly assign participants to receive either a new drug or a placebo and measure their recovery rates.

Question 4

What is the main purpose of random sampling in statistics?

Accepted Answer

To ensure every member of the population has an equal chance of being selected.

Question 5

Which of the following best describes confounding in an experiment?

Accepted Answer

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

Question 6

Given a data set with the following values: 2, 4, 4, 6, 8, what is the median?

Accepted Answer

$$4$$

Question 7

Which measure of spread is most resistant to outliers?

Accepted Answer

Interquartile range (IQR)

Question 8

A histogram of exam scores is skewed right. Which of the following is most likely true?

Accepted Answer

The mean is greater than the median.

Question 9

If a data set has a mean of $$50$$ and a standard deviation of $$5$$, what is the z-score of a value $$60$$?

Accepted Answer

$$2$$

Question 10

Which of the following statements about boxplots is correct?

Accepted Answer

Boxplots display the median, quartiles, and potential outliers of a data set.

Question 11

A researcher wants to compare the test scores of students from two different schools. Which graphical summary is most appropriate?

Accepted Answer

Side-by-side boxplots

Question 12

Which of the following is NOT a measure of center?

Accepted Answer

Interquartile range (IQR)

Question 13

In a scatter plot, what does a positive linear relationship indicate?

Accepted Answer

As one variable increases, the other variable also increases.

Question 14

Which formula is used to calculate the variance of a sample?

Accepted Answer

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

Question 15

Which of the following best describes an operational definition?

Accepted Answer

A definition that explains how a variable will be measured in a specific study.

Question 16

If the first quartile ($$Q_1) of a $$data set is $$20$$ and the third quartile ($$Q_3) is$$ $$40$$, what is the interquartile range (IQR)?

Accepted Answer

$$20$$

Question 17

Which of the following is a categorical variable?

Accepted Answer

Type of car (sedan, SUV, truck)

Question 18

A convenience sample is most likely to:

Accepted Answer

Produce a biased sample that may not represent the population.

Question 19

Which of the following is true about the correlation coefficient $$r$$?

Accepted Answer

$$r$$ measures the strength and direction of a linear relationship between two quantitative variables.

Question 20

If a data set contains an extreme value much lower than all others, this value is called:

Accepted Answer

An outlier

Statistics Exam 1 Study Guide: Data Collection, Summarization, and Relationships

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