Question 1

Which of the following best describes the difference between a parameter and a statistic?

Accepted Answer

A parameter is a numerical summary of a population, while a statistic is a numerical summary of a sample.

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. What type of study is this?

Accepted Answer

Experimental study

Question 3

Which sampling method involves dividing the population into groups based on a characteristic, then randomly selecting some groups and including all members of those groups in the sample?

Accepted Answer

Cluster sampling

Question 4

A variable that can take on any value within a given range, such as height or weight, is best described as:

Accepted Answer

Numerical, continuous

Question 5

Which graphical display is most appropriate for showing the distribution of a categorical variable such as favorite ice cream flavor?

Accepted Answer

Pie chart

Question 6

Given the following data set: 2, 4, 4, 6, 8. What is the mode?

Accepted Answer

$$4$$

Question 7

If the first quartile ($$Q_1) of a $$data set is $$10$$ and the third quartile ($$Q_3) is$$ $$30$$, what is the interquartile range (IQR)?

Accepted Answer

$$20$$

Question 8

A boxplot is most useful for:

Accepted Answer

Showing the five-number summary and identifying outliers

Question 9

Which property is true for the correlation coefficient $$r$$?

Accepted Answer

$$-1 \leq r \leq 1$$

Question 10

A scatter diagram shows a strong positive linear relationship between two variables. Which value is most likely for the correlation coefficient $$r$$?

Accepted Answer

$$0.90$$

Question 11

Which of the following statements best explains why association does not imply causation?

Accepted Answer

Because two variables can be related due to a lurking variable or coincidence

Question 12

Given the regression equation $$y = 2x + 5$$, what is the predicted value of $$y$$ when $$x = 4$$?

Accepted Answer

$$13$$

Question 13

If the actual value of $$y is$$ $$20$$ and the predicted value from the regression equation is $$15$$, what is the residual?

Accepted Answer

$$5$$

Question 14

In the context of a regression analysis, what does the slope of the least squares regression line represent?

Accepted Answer

The change in $$y$$ for a one-unit increase in $$x$$

Question 15

If the coefficient of determination $$R^2 is$$ $$0.81$$, what does this mean in the context of a linear model?

Accepted Answer

81% of the variation in $$y is $$explained by the linear relationship with $$x$$

Question 16

A residual plot shows a random scatter of points around zero. What does this indicate about the linearity assumption?

Accepted Answer

The linearity assumption is likely satisfied

Question 17

A frequency table is used to:

Accepted Answer

Summarize how often each value occurs in a data set

Question 18

Which sampling method selects every $$kth $$individual from a list after a random start?

Accepted Answer

Systematic sampling

Question 19

A hospital wants to compare patient satisfaction scores between two departments. Which graphical display would best show the comparison?

Accepted Answer

Side by side bar chart

Question 20

A student calculates the mean and median of a data set and finds the mean is much higher than the median. What does this suggest about the distribution?

Accepted Answer

The distribution is right-skewed

Introductory Statistics Midterm Study Guide: Chapters 1–4

Guida di studio - Domande di pratica

Study guide - Flashcard