Question 1

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

Accepted Answer

A population includes all members of a defined group, while a sample is a subset of the population selected for analysis.

Question 2

A pharmaceutical company wants to estimate the average recovery time for a new medication. They select 200 patients from a hospital and record their recovery times. Which term best describes the 200 patients?

Accepted Answer

Sample

Question 3

Which of the following is a quantitative variable?

Accepted Answer

The number of cars owned by a family

Question 4

A researcher collects data on the blood types (A, B, AB, O) of 1000 people. What level of measurement is this data?

Accepted Answer

Nominal

Question 5

Which of the following is an example of an observational study?

Accepted Answer

A scientist records the heights of plants in a field without interfering with their growth.

Question 6

Suppose the mean score on a statistics exam is 75 with a standard deviation of 8. If a student scored 91, what is their z-score? Use the formula $$z = \frac{x - \mu}{\sigma}.$$

Accepted Answer

$$z = 2$$

Question 7

A data set has the following values: 2, 4, 4, 6, 8. What is the median?

Accepted Answer

4

Question 8

Which of the following statements about the mean and median is TRUE for a right-skewed distribution?

Accepted Answer

The mean is greater than the median.

Question 9

A company wants to display the distribution of salaries among its employees. Which type of graph is most appropriate?

Accepted Answer

Histogram

Question 10

If the probability of rain tomorrow is 0.3, what is the probability that it will NOT rain?

Accepted Answer

0.7

Question 11

A fair six-sided die is rolled. What is the probability of rolling a number greater than 4?

Accepted Answer

$$\frac{1}{3}$$

Question 12

A bag contains 5 red, 3 blue, and 2 green marbles. If one marble is drawn at random, what is the probability it is blue?

Accepted Answer

$$\frac{3}{10}$$

Question 13

Which of the following is NOT a requirement for a binomial experiment?

Accepted Answer

The probability of success must change from trial to trial.

Question 14

A normal distribution has mean $$\mu = 50$$ and standard deviation $$\sigma = 5. $$What percentage of data falls within one standard deviation of the mean (between 45 and 55)?

Accepted Answer

Approximately 68%

Question 15

A researcher wants to estimate the average height of adult males in a city. Which sampling method is most likely to produce a representative sample?

Accepted Answer

Simple random sampling

Question 16

A 95% confidence interval for the mean weight of apples in an orchard is (150g, 170g). What does this mean?

Accepted Answer

We are 95% confident that the true mean weight of apples is between 150g and 170g.

Question 17

A medical researcher tests whether a new drug lowers blood pressure. The null hypothesis is $$H_0$$: \mu = 120$$ mmHg. The sample mean is 115 mmHg, and the p-value is 0.03. At $$\alpha = 0.05$$, what is the correct conclusion?

Accepted Answer

Reject the null hypothesis; there is evidence the drug lowers blood pressure.

Question 18

Which of the following is an example of a Type I error in hypothesis testing?

Accepted Answer

Rejecting a true null hypothesis.

Question 19

A study finds a correlation coefficient $$r = 0.85$$ between hours studied and exam scores. What does this indicate?

Accepted Answer

There is a strong positive linear relationship between hours studied and exam scores.

Question 20

A researcher wants to predict a student's final grade based on the number of hours studied using the regression equation $$\hat{y} = 50 + 5x$$, where $$x is $$hours studied. What is the predicted grade for a student who studies 6 hours?

Accepted Answer

$$\hat{y} = 80$$

Introductory Statistics Course Schedule and Chapter Overview

Guida di studio - Domande di pratica

Study guide - Flashcard