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, used to make inferences about the population.

Question 2

A pharmaceutical company wants to test a new drug. They randomly assign patients to either the drug or a placebo group and compare outcomes. What type of study is this?

Accepted Answer

Randomized comparative experiment

Question 3

Which of the following variables is discrete?

Accepted Answer

The number of cars sold at a dealership each day

Question 4

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

Accepted Answer

Exercise

Question 5

Which type of graph is most appropriate for displaying the distribution of a single quantitative variable?

Accepted Answer

Histogram

Question 6

Given the data set: 45, 51, 56, 63, 64, 68, 70, 75, 75, 78, 80, 84, 84, 84, 88, 90, 92, 95, 99, what is the median?

Accepted Answer

78

Question 7

Which measure of spread is most resistant to outliers?

Accepted Answer

Interquartile range (IQR)

Question 8

A box and whisker plot is most useful for:

Accepted Answer

Visualizing the spread and identifying outliers in a data set

Question 9

If a data set is strongly skewed to the right, which measure of central tendency is most affected?

Accepted Answer

Mean

Question 10

The empirical rule states that for a normal distribution, approximately what percent of data falls within two standard deviations of the mean?

Accepted Answer

$$95\%$$

Question 11

Given the following five-number summary: $$45$$, $$64$$, $$78$$, $$90$$, $$99$$, what is the interquartile range (IQR)?

Accepted Answer

$$26$$

Question 12

Which formula correctly calculates the sample standard deviation $$s$$ for a data set $$x_1$$, $$x_2$$, ..., x_n$$?

Accepted Answer

$$s = \sqrt{\frac{1}{n-1} \sum_{i=1}^{n} (x_i - \bar{x})^2$}$$

Question 13

A scatterplot is best used to:

Accepted Answer

Display the relationship between two quantitative variables

Question 14

If the correlation coefficient $$r$$ between hours studied and grades is $$0.95$$, what does this indicate?

Accepted Answer

There is a strong positive linear relationship.

Question 15

Suppose the regression equation relating hours studied ($$x) to $$grades ($$y) is$$ $$y = 10x + 40. $$What is the predicted grade for a student who studies $$4$$ hours?

Accepted Answer

$$y = 80$$

Question 16

In the regression equation $$y = 10x + 40$$, what does the coefficient $$10$$ represent?

Accepted Answer

The increase in grade for each additional hour studied

Question 17

A residual in linear regression is:

Accepted Answer

The actual value minus the predicted value

Question 18

Which of the following is a parameter, not a statistic?

Accepted Answer

Population mean $$\mu$$

Question 19

A matched pair experiment is best described as:

Accepted Answer

Pairing subjects based on similar characteristics and giving each pair both treatments

Question 20

Which of the following is NOT a common bias in data collection?

Accepted Answer

Randomization bias

Introductory Statistics: Study Guide for Chapters 1–4

Guida di studio - Domande di pratica

Study guide - Flashcard