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.

Question 2

A researcher wants to estimate the average height of all students at Tulsa Community College. She randomly selects 100 students and calculates their average height. In this scenario, what is the sample statistic?

Accepted Answer

The average height calculated from the 100 selected students.

Question 3

Which of the following is NOT a measure of central tendency?

Accepted Answer

Range

Question 4

Given the data set: 2, 4, 4, 6, 8, what is the median?

Accepted Answer

$$4$$

Question 5

Which formula correctly calculates the variance $$s^2 of a $$sample with $$n$$ values $$x_1$$, $$x_2$$, ..., x_n$$ and sample mean $$\overline{x}$$?

Accepted Answer

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

Question 6

A fair coin is flipped three times. What is the probability of getting exactly two heads?

Accepted Answer

$$\frac{3}{8}$$

Question 7

Which of the following best describes a normal distribution?

Accepted Answer

A distribution that is symmetric and bell-shaped.

Question 8

If a 95% confidence interval for a population mean is $$(50, 60)$$, which of the following statements is correct?

Accepted Answer

We are 95% confident that the population mean is between 50 and 60.

Question 9

Which of the following is the correct formula for the standard error of the mean for a sample of size $$n$$ with standard deviation $$s$$?

Accepted Answer

$$\frac{s}{\sqrt{n}}$$

Question 10

A medical researcher tests whether a new drug lowers blood pressure more than a placebo. Which is the null hypothesis $$H_0$$ for this test?

Accepted Answer

$$H_0$$: The new drug does not lower blood pressure more than the placebo.

Question 11

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

Accepted Answer

Rejecting the null hypothesis when it is actually true.

Question 12

A frequency distribution is used to:

Accepted Answer

Organize data into categories or intervals and show how often each occurs.

Question 13

Which of the following is the correct formula for the probability of $$k$$ successes in $$n$$ independent Bernoulli trials with probability $$p of $$success (binomial probability)?

Accepted Answer

$$P(X = k) = {n \choose k} p^k (1-p$$)^{n-k}$$

Question 14

Which of the following best describes the purpose of hypothesis testing in statistics?

Accepted Answer

To make inferences about a population based on sample data.

Question 15

A student calculates a $$z-$$score of $$2.5$$ for a test score. What does this mean?

Accepted Answer

The test score is $$2.5$$ standard deviations above the mean.

Question 16

Which of the following is a real-world example of using a confidence interval?

Accepted Answer

A polling organization reports that 60% of voters support a candidate, with a margin of error of 3%.

Question 17

If the probability of an event is $$0.2$$, what is the probability that the event does NOT occur?

Accepted Answer

$$0.8$$

Question 18

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

Accepted Answer

Favorite color

Question 19

A student wants to test if the average time spent studying per week by TCC students is different from 10 hours. Which statistical test should be used?

Accepted Answer

One-sample $$t-$$test for the mean

Question 20

Which of the following is the correct formula for the mean $$\overline{x} of$$ $$n$$ values $$x_1$$, $$x_2$$, ..., x_n$$?

Accepted Answer

$$\overline{x} = \frac{\sum_{i=1}^n x_i}{n}$$

Elementary Statistics Course Syllabus and Study Guide

Guida di studio - Domande di pratica

Study guide - Flashcard