Chapter 9 Quiz

You want to test if more than 20% of homes in a neighborhood have recently been sold through a short sale, at a foreclosure auction, or by the bank following an unsuccessful foreclosure auction. You take a sample of 60 homes from this neighborhood and find that 14 fit your criteria. The appropriate null and alternative hypotheses are ________. A. H0: p ≤ 0.20, HA: p > 0.20 B. H0: p = 0.20, HA: p ≠ 0.20

A. H0: p ≤ 0.20, HA: p > 0.20

A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 3.50. A sample of 36 honors students is taken and is found to have a mean GPA equal to 3.60. The population standard deviation is assumed to equal 0.40. To establish whether the mean GPA exceeds 3.50, the appropriate hypotheses are ________. A. H0: μ ≤ 3.50, HA: μ > 3.50 B. H0: μ ≥ 3.50, HA: μ < 3.50

A. H0: μ ≤ 3.50, HA: μ > 3.50

The Department of Education would like to test the hypothesis that the average debt load of graduating students with a bachelor's degree is equal to $17,000. A random sample of 34 students had an average debt load of $18,200. It is believed that the population standard deviation for student debt load is $4,200. The α is set to 0.05. The p-value for this hypothesis test would be ________. A. 0.1310 B. 0.0957 C. 0.0475 D. 0.0219

B. 0.0957

A university interested in tracking its honors program believes that the proportion of graduates with a GPA of 3.00 or below is less than 0.20. In a sample of 200 graduates, 30 students have a GPA of 3.00 or below. In testing the university's belief, the appropriate hypotheses are ________. A. H0: p = 0.15, HA: p ≠ 0.15 B. H0: p ≥ 0.20, HA: p < 0.20

B. H0: p ≥ 0.20, HA: p < 0.20

A Type II error occurs when we ________. A. reject the null hypothesis when it is actually true B. reject the null hypothesis when it is actually false C. do not reject the null hypothesis when it is actually true D. do not reject the null hypothesis when it is actually false

D. do not reject the null hypothesis when it is actually false

A schoolteacher is worried that the concentration of dangerous, cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L. The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. To test whether the average level of radon gas is greater than the safe level, the appropriate hypotheses are ________. A. H0: μ ≤ 4.0, HA: μ > 4.0 B. H0: μ = 4.0, HA: μ ≠ 4.0 C. H0: μ ≥ 4.4, HA: μ < 4.4

A. H0: μ ≤ 4.0, HA: μ > 4.0

Expedia would like to test if the average round-trip airfare between Philadelphia and Dublin is less than $1,200. Which of the following hypothesis tests should be performed? A. Left-tailed B. Right-tailed C. Two-tailed D. There is not enough information to answer.

A. Left-tailed

For a given sample size n, ________. A. decreasing the probability of a Type I error α will increase the probability of a Type II error β B. decreasing the probability of a Type I error α will decrease the probability of a Type II error β C. changing the probability of a Type I error α will have no impact on the probability of a Type II error β D. increasing the probability of a Type I error α will increase the probability of a Type II error β as long as σ is known

A. decreasing the probability of a Type I error α will increase the probability of a Type II error β

When we reject the null hypothesis when it is actually false, we have committed ________. A. no error B. a Type I error C. a Type II error D. a Type I error and a Type II error

A. no error

The Institute of Education Sciences measures the high school dropout rate as the percentage of 16- through 24-year-olds who are not enrolled in school and have not earned a high school credential. Last year, the high school dropout rate was 8.1%. A polling company recently took a survey of 1,000 people between the ages of 16 and 24 and found that 6.5% of them are high school dropouts. The polling company would like to determine whether the dropout rate has decreased. At a 5% significance level, the decision is to ________. A. reject H0; we can conclude that the high school dropout rate has decreased B. reject H0; we cannot conclude that the high school dropout rate has decreased C. do not reject H0; we can conclude that the high school dropout rate has decreased D. do not reject H0; we cannot conclude that the high school dropout rate has decreased

A. reject H0; we can conclude that the high school dropout rate has decreased

A university interested in tracking its honors program believes that the proportion of graduates with a GPA of 3.00 or below is less than 0.20. In a sample of 200 graduates, 30 students have a GPA of 3.00 or below. At a 5% significance level, the decision is to ________. A. reject H0; we can conclude that the proportion of graduates with a GPA of 3.00 or below is significantly less than 0.20 B. reject H0; we cannot conclude that the proportion of graduates with a GPA of 3.00 or below is significantly less than 0.20 C. not reject H0; we can conclude that the proportion of graduates with a GPA of 3.00 or below is significantly less than 0.20 D. not reject H0; we cannot conclude that the proportion of graduates with a GPA of 3.00 or below is significantly less than 0.20

A. reject H0; we can conclude that the proportion of graduates with a GPA of 3.00 or below is significantly less than 0.20

If the p-value for a hypothesis test is 0.027 and the chosen level of significance is α = 0.05, then the correct conclusion is to ________. A. reject the null hypothesis B. not reject the null hypothesis C. reject the null hypothesis if σ = 10 D. not reject the null hypothesis if σ = 10

A. reject the null hypothesis

A Type I error occurs when we ________. A. reject the null hypothesis when it is actually true B. reject the null hypothesis when it is actually false C. do not reject the null hypothesis when it is actually true D. do not reject the null hypothesis when it is actually false

A. reject the null hypothesis when it is actually true

A hypothesis test regarding the population mean is based on ________. A. the sampling distribution of the sample mean B. the sampling distribution of the sample variance C. the sampling distribution of the sample proportion D. the sampling distribution of the sample standard deviation

A. the sampling distribution of the sample mean

If the chosen significance level is α = 0.05, then ________. A. there is a 5% probability of rejecting a true null hypothesis B. there is a 5% probability of accepting a true null hypothesis C. there is a 5% probability of rejecting a false null hypothesis D. there is a 5% probability of accepting a false null hypothesis

A. there is a 5% probability of rejecting a true null hypothesis.

Which of the following are two-tailed tests? A. H0: μ ≤ 10, HA: μ > 10 B. H0: μ = 10, HA: μ ≠ 10 C. H0: μ ≥ 400, HA: μ < 400 D. Both H0: μ ≤ 10, HA: μ > 10 and H0: μ ≥ 400, HA: μ < 400

B. H0: μ = 10, HA: μ ≠ 10

The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership. The dealership has historically had 800 customers per day. The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750. Assume that the population standard deviation is 350.To determine whether there has been a decrease in the average number of customers visiting the dealership daily, the appropriate hypotheses are ________. A. H0: μ ≤ 800, HA: μ > 800 B. H0: μ ≥ 800, HA: μ < 800

B. H0: μ ≥ 800, HA: μ < 800

What is the decision rule when using the p-value approach to hypothesis testing? A. Reject H0 if the p-value > α. B. Reject H0 if the p-value < α. C. Do not reject H0 if the p-value < 1 - α. D. Do not reject H0 if the p-value > 1 - α.

B. Reject H0 if the p-value < α.

The alternative hypothesis typically ________. A. corresponds to the presumed default state of nature B. contests the status quo, for which a corrective action may be required C. states the probability of rejecting the null hypothesis when it is false D. states the probability of rejecting the null hypothesis when it is true

B. contests the status quo, for which a corrective action may be required

If the p-value for a hypothesis test is 0.07 and the chosen level of significance is α = 0.05, then the correct conclusion is to ________. A. reject the null hypothesis B. not reject the null hypothesis C. reject the null hypothesis if σ = 10 D. not reject the null hypothesis if σ = 10

B. not reject the null hypothesis

The null hypothesis in a hypothesis test refers to ________. A. the desired outcome B. the default state of nature C. the altered state of nature D. the desired state of nature

B. the default state of nature

A university interested in tracking its honors program believes that the proportion of graduates with a GPA of 3.00 or below is less than 0.20. In a sample of 200 graduates, 30 students have a GPA of 3.00 or below. The value of the test statistic and its associated p-value are ________. A. t199 = -1.77 and p-value = 0.0385 B. z = -1.77 and p-value = 0.0385 C. t199 = -1.77 and p-value = 0.0768 D. z = -1.77 and p-value = 0.0768

B. z = -1.77 and p-value = 0.0385

A schoolteacher is worried that the concentration of dangerous, cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L. The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. The value of the test statistic is A. t35 = -2.40 B. z = -2.40 C. t35 = 2.40 D. z = 2.40

C. t35 = 2.40

A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 3.50. A sample of 36 honors students is taken and is found to have a mean GPA equal to 3.60. The population standard deviation is assumed to equal 0.40. The value of the test statistic is ________. A. z = -1.50 B. t35 = -1.50 C. z = 1.50 D. t35 = 1.50

C. z = 1.50

A 99% confidence interval for the population mean yields the following results: [−3.79, 5.86]. At the 1% significance level, what decision should be made regarding the following hypothesis test with H0: μ = 0, HA: μ ≠ 0? A. Reject H0; we can conclude that the mean differs from zero. B. Reject H0; we cannot conclude that the mean differs from zero. C. Do not reject H0; we can conclude that the mean differs from zero. D. Do not reject H0; we cannot conclude that the mean differs from zero.

D. Do not reject H0; we cannot conclude that the mean differs from zero.

Many cities around the United States are installing LED streetlights, in part to combat crime by improving visibility after dusk. An urban police department claims that the proportion of crimes committed after dusk will fall below the current level of 0.84 if LED streetlights are installed. Specify the null and alternative hypotheses to test the police department's claim. A. H0: p = 0.84 and HA: p ≠ 0.84 B. H0: p < 0.84 and HA: p ≥ 0.84 C. H0: p ≤ 0.84 and HA: p > 0.84 D. H0: p ≥ 0.84 and HA: p < 0.84

D. H0: p ≥ 0.84 and HA: p < 0.84

Which of the following represents an appropriate set of hypotheses? *Don't know what answers (A & B) symbols were. Doesn't show in quiz* A. H0: ? = 0, HA: ? ≠ 0 B. H0: ? < 0, HA: ? > 0 C. H0: μ < 0, HA: μ > 0 D. H0: μ = 0, HA: μ ≠ 0

D. H0: μ = 0, HA: μ ≠ 0

Which of the following answers represents the objective of a hypothesis test? A. Rejecting the null hypothesis when it is true. B. Rejecting the null hypothesis when it is false. C. Not rejecting the null hypothesis when it is true. D. Rejecting the null hypothesis when it is false and not rejecting the null hypothesis when it is true.

D. Rejecting the null hypothesis when it is false and not rejecting the null hypothesis when it is true.

In general, the null and alternative hypotheses are ________. A. additive B. correlated C. multiplicative D. mutually exclusive

D. mutually exclusive

A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 3.50. A sample of 36 honors students is taken and is found to have a mean GPA equal to 3.60. The population standard deviation is assumed to equal 0.40. At a 5% significance level, the decision is to ________. A. reject H0 we can conclude that the mean GPA is significantly greater than 3.50 B. reject H0 we cannot conclude that the mean GPA is significantly greater than 3.50 C. not reject H0 we can conclude that the mean GPA is significantly greater than 3.50 D. not reject H0 we cannot conclude that the mean GPA is significantly greater than 3.50

D. not reject H0 we cannot conclude that the mean GPA is significantly greater than 3.50