Question 1

Which of the following best describes the difference between descriptive and inferential statistics?

Accepted Answer

Descriptive statistics summarize and organize data, while inferential statistics use sample data to make generalizations about a population.

Question 2

A researcher collects the heights (in cm) of 100 randomly selected college students and wants to display the distribution. Which graphical display is most appropriate?

Accepted Answer

Histogram

Question 3

Which of the following is NOT a measure of center?

Accepted Answer

Range

Question 4

Suppose the scores on a statistics exam are normally distributed with a mean of 75 and a standard deviation of 8. What is the z-score for a student who scored 91?

Accepted Answer

$$z = \frac{91 - 75}{8} = 2$$

Question 5

A medical study finds a correlation coefficient $$r = 0.85$$ between hours of exercise per week and HDL cholesterol levels. Which of the following is the best interpretation?

Accepted Answer

There is a strong positive linear relationship between hours of exercise and HDL cholesterol.

Question 6

Which of the following statements about the binomial distribution is TRUE?

Accepted Answer

There are a fixed number of trials, each with two possible outcomes.

Question 7

A fair coin is flipped 10 times. What is the probability of getting exactly 6 heads? Use the binomial formula.

Accepted Answer

$$P(X=6) = \binom{10}{6} (0.5)^6$ (0.5)^4$

Question 8

Which of the following is the correct formula for a 95% confidence interval for a population mean $$\mu$$ when the population standard deviation $$\sigma is $$known?

Accepted Answer

$$\bar{x} \pm z^* \frac{\sigma}{\sqrt{n}}$$

Question 9

A pharmaceutical company wants to test if a new drug lowers blood pressure more than the current standard. Which hypothesis test should they use?

Accepted Answer

A two-sample t-test for means

Question 10

If the p-value for a hypothesis test is 0.03 and the significance level $$\alpha is 0.05$$, what is the correct conclusion?

Accepted Answer

Reject the null hypothesis.

Question 11

Which of the following best describes a Type I error in hypothesis testing?

Accepted Answer

Rejecting a true null hypothesis.

Question 12

A survey asks 500 randomly selected adults if they support a new recycling law. 320 say yes. What is the sample proportion $$\hat{p}$$?

Accepted Answer

$$\hat{p} = \frac{320}{500} = 0.64$$

Question 13

Which of the following is a requirement for using the normal approximation to the binomial distribution?

Accepted Answer

$$np \geq 5$$ and $$n(1-p) \geq 5$$

Question 14

A scatterplot of two variables shows a strong upward trend. Which of the following statistics would best quantify this relationship?

Accepted Answer

Correlation coefficient $$r$$

Question 15

Which of the following is the correct formula for the sample variance $$s^2$$?

Accepted Answer

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

Question 16

A hospital administrator wants to know if the average wait time in the ER has changed from last year’s mean of 45 minutes. Which hypothesis test is most appropriate?

Accepted Answer

One-sample t-test for the mean

Question 17

Which of the following is an example of a qualitative (categorical) variable?

Accepted Answer

Favorite type of cuisine

Question 18

A 95% confidence interval for the mean weight of apples in an orchard is (140g, 160g). Which of the following is a correct interpretation?

Accepted Answer

We are 95% confident that the true mean weight of apples is between 140g and 160g.

Question 19

Which of the following best describes the purpose of a regression analysis?

Accepted Answer

To predict the value of one variable based on another variable

Question 20

A study finds that the mean number of hours college students sleep per night is 6.8 with a standard deviation of 1.2. If a student sleeps 9.2 hours, what is their z-score?

Accepted Answer

$$z = \frac{9.2 - 6.8}{1.2} = 2$$

Statistics I (MATH 250 BDE) Syllabus and Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards