Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 < µ2; α = 0.10. Assume σ12 ≠ σ22 Sample statistics: x1 = 0.015, s1 = 0.011, n1 = 8 and x2 = 0.019, s2 = 0.004, n2 = 6
> a. display the data in a scatter plot, b. calculate the sample correlation coefficient r, and c. describe the type of correlation and interpret the correlation in the context of the data. The intelligence quotient (IQ) scores and brain sizes, as measur
> Use the multiple regression equation to predict the y-values for the values of the independent variables. Use the regression equation found in Exercise 25. a. x1 = 10, x2 = 0.7 b. x1 = 15, x2 = 1.1 c. x1 = 13, x2 = 1.0 d. x1 = 9, x2 = 0.8
> Use technology to find a. the multiple regression equation for the data shown in the table, b. the standard error of estimate, and c. the coefficient of determination. Interpret the result. The table shows the numbers of acres planted, the numbers of
> Use technology to find a. the multiple regression equation for the data shown in the table, b. the standard error of estimate, and c. the coefficient of determination. Interpret the result. The table shows the carbon monoxide, tar, and nicotine conten
> Construct the indicated prediction interval and interpret the results. Construct a 99% prediction interval for the price of a gas grill in Exercise 18 with a usable cooking area of 900 square inches.
> Construct the indicated prediction interval and interpret the results. Construct a 99% prediction interval for the top speed of a hybrid or electric car in Exercise 17 that has a combined city and highway fuel economy of 90 miles per gallon equivalent.
> Construct the indicated prediction interval and interpret the results. Construct a 95% prediction interval for the fuel efficiency of an automobile in Exercise 12 that has an engine displacement of 265 cubic inches
> Construct the indicated prediction interval and interpret the results. Construct a 95% prediction interval for the number of hours of sleep for an adult in Exercise 11 who is 45 years old.
> Match each P-value with the graph that displays its area without performing any calculations. Explain your reasoning. P = 0.0688 and P = 0.2802 (a) (b) -2 -i ó i 2 3 -ż -i o i /2 2 = 1.82 Z = 1.08
> Construct the indicated prediction interval and interpret the results. Construct a 90% prediction interval for the average time women spend per day watching television in Exercise 10 when the average time men spend per day watching television is 3.08 hou
> a. display the data in a scatter plot, b. calculate the sample correlation coefficient r, and c. describe the type of correlation and interpret the correlation in the context of the data. The numbers of wildland fires (in thousands) and wildland acres
> Construct the indicated prediction interval and interpret the results. Construct a 90% prediction interval for the amount of milk produced in Exercise 9 when there are an average of 9275 milk cows.
> Use the value of the correlation coefficient r to calculate the coefficient of determination r2. What does this tell you about the explained variation of the data about the regression line? about the unexplained variation? r = 0.795
> Use the value of the correlation coefficient r to calculate the coefficient of determination r2. What does this tell you about the explained variation of the data about the regression line? about the unexplained variation? r = 0.642
> Use the value of the correlation coefficient r to calculate the coefficient of determination r2. What does this tell you about the explained variation of the data about the regression line? about the unexplained variation? r = -0.937
> Use the value of the correlation coefficient r to calculate the coefficient of determination r2. What does this tell you about the explained variation of the data about the regression line? about the unexplained variation? r = -0.450
> Find the equation of the regression line for the data. Then construct a scatter plot of the data and draw the regression line. (Each pair of variables has a significant correlation.) Then use the regression equation to predict the value of y for each of
> Match each P-value with the graph that displays its area without performing any calculations. Explain your reasoning. P = 0.0089 and P = 0.3050 (a) (b) -3 -2 -1 to i 2 3 -2 -1 0 1 2 3 z=-2.37 2=-0.51
> Find the equation of the regression line for the data. Then construct a scatter plot of the data and draw the regression line. (Each pair of variables has a significant correlation.) Then use the regression equation to predict the value of y for each of
> Find the equation of the regression line for the data. Then construct a scatter plot of the data and draw the regression line. (Each pair of variables has a significant correlation.) Then use the regression equation to predict the value of y for each of
> a. display the data in a scatter plot, b. calculate the sample correlation coefficient r, and c. describe the type of correlation and interpret the correlation in the context of the data. The numbers of pass attempts and passing yards for seven profess
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision
> Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 ≠ µ2; α = 0.05 Population statistics: σ1 =
> Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 < µ2; α = 0.10 Population statistics: σ1 =
> Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 = µ2; α = 0.01 Population statistics: σ1 =
> Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 ≥ µ2; α = 0.05 Population statistics: σ1 =
> Classify the two samples as independent or dependent and justify your answer. Sample 1: The fuel efficiencies of 12 cars Sample 2: The fuel efficiencies of the same 12 cars using an alternative fuel
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret
> Find the P-value for the hypothesis test with the standardized test statistic z. Decide whether to reject H0 for the level of significance α. Two-tailed test z = 1.95 α = 0.08
> Classify the two samples as independent or dependent and justify your answer. Sample 1: The fuel efficiencies of 20 sports utility vehicles Sample 2: The fuel efficiencies of 20 minivans
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret
> Determine whether a normal sampling distribution can be used. If it can be used, test the claim about the difference between two population proportions p1 and p2 at the level of significance α. Assume the samples are random and independent. Claim: p1 < p
> Determine whether a normal sampling distribution can be used. If it can be used, test the claim about the difference between two population proportions p1 and p2 at the level of significance α. Assume the samples are random and independent. Claim: p1 > p
> Determine whether a normal sampling distribution can be used. If it can be used, test the claim about the difference between two population proportions p1 and p2 at the level of significance α. Assume the samples are random and independent. Claim: p1 ≤ p
> Determine whether a normal sampling distribution can be used. If it can be used, test the claim about the difference between two population proportions p1 and p2 at the level of significance α. Assume the samples are random and independent. Claim: p1 = p
> Test the claim about the mean of the differences for a population of paired data at the level of significance α. Assume the samples are random and dependent, and the populations are normally distributed. Claim: µd ≠ 0; α = 0.05. Sample statistics: d = 17
> Test the claim about the mean of the differences for a population of paired data at the level of significance α. Assume the samples are random and dependent, and the populations are normally distributed. Claim: µd ≤ 0; α = 0.10. Sample statistics: d = 10
> Find the P-value for the hypothesis test with the standardized test statistic z. Decide whether to reject H0 for the level of significance α. Two-tailed test z = -1.68 α = 0.05
> Test the claim about the mean of the differences for a population of paired data at the level of significance α. Assume the samples are random and dependent, and the populations are normally distributed. Claim: µd < 0; α = 0.10. Sample statistics: d = 3.
> Classify the two samples as independent or dependent and justify your answer. Sample 1: The weights of 39 dogs Sample 2: The weights of 39 cats
> Test the claim about the mean of the differences for a population of paired data at the level of significance α. Assume the samples are random and dependent, and the populations are normally distributed. Claim: µd = 0; α = 0.01. Sample statistics: d = 8.
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic t, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic t, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret
> Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 > µ2; α = 0.05. Assume σ12 ≠ σ22 Sample sta
> Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 ≠ µ2; α = 0.01. Assume σ12 = σ22 Sample sta
> Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 ≥ µ2; α = 0.01. Assume σ12 = σ22 Sample sta
> Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 ≤ µ2; α = 0.10. Assume σ12 ≠ σ22 Sample sta
> Find the P-value for the hypothesis test with the standardized test statistic z. Decide whether to reject H0 for the level of significance α. Right-tailed test z = 1.23 α = 0. 10
> Test the claim about the difference between two population means µ1 and µ2 at the level of significance α. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ1 = µ2; α = 0.05. Assume σ12 = σ22 Sample sta
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision
> Classify the two samples as independent or dependent and justify your answer. Sample 1: The weights of 43 adults Sample 2: The weights of the same 43 adults after participating in a diet and exercise program
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic x2, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decisio
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic x2, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decisio
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic x2, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decisio
> In a right-tailed test where P < α, does the standardized test statistic lie to the left or the right of the critical value? Explain your reasoning.
> When P > α, does the standardized test statistic lie inside or outside of the rejection region(s)? Explain your reasoning.
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision
> The P-value for a hypothesis test is shown. Use the P-value to decide whether to reject H0 when the level of significance is a. α = 0.01, b. α = 0.05, and c. α = 0.10. P = 0.0691
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision
> a. identify the claim and state H0 and Ha, b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic z, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision
> a. identify the claim and state H0 and Ha. b. find the standardized test statistic z. c. find the corresponding P-value. d. decide whether to reject or fail to reject the null hypothesis. e. interpret the decision in the context of the original claim
> The statement represents a claim. Write its complement and state which is H0 and which is Ha. σ = 0.63
> a. identify the claim and state H0 and Ha. b. find the standardized test statistic z. c. find the corresponding P-value. d. decide whether to reject or fail to reject the null hypothesis. e. interpret the decision in the context of the original claim
> a. identify the claim and state H0 and Ha. b. find the standardized test statistic z. c. find the corresponding P-value. d. decide whether to reject or fail to reject the null hypothesis. e. interpret the decision in the context of the original claim
> a. identify the claim and state H0 and Ha. b. find the standardized test statistic z. c. find the corresponding P-value. d. decide whether to reject or fail to reject the null hypothesis. e. interpret the decision in the context of the original claim
> a. identify the claim and state H0 and Ha. b. find the standardized test statistic z. c. find the corresponding P-value. d. decide whether to reject or fail to reject the null hypothesis. e. interpret the decision in the context of the original claim
> a. identify the claim and state H0 and Ha. b. find the standardized test statistic z. c. find the corresponding P-value. d. decide whether to reject or fail to reject the null hypothesis. e. interpret the decision in the context of the original claim
> Test the claim about the population mean µ at the level of significance α. Assume the population is normally distributed. Claim: µ ≤ 22,500; α = 0.01; σ = 1200 Sample statistics: x = 23,500, n = 45
> The P-value for a hypothesis test is shown. Use the P-value to decide whether to reject H0 when the level of significance is a. α = 0.01, b. α = 0.05, and c. α = 0.10. P = 0.0461
> Test the claim about the population mean µ at the level of significance α. Assume the population is normally distributed. Claim: µ ≠ 5880; α = 0.03; σ = 413 Sample statistics: x = 5771, n = 67
> According to a study of employed U.S. adults ages 18 and over, the mean number of workdays missed due to illness or injury in the past 12 months is 3.5 days. You randomly select 25 employed U.S. adults ages 18 and over and find that the mean number of wo
> Homeowners claim that the mean speed of automobiles traveling on their street is greater than the speed limit of 35 miles per hour. A random sample of 100 automobiles has a mean speed of 36 miles per hour. Assume the population standard deviation is 4 mi
> Find the P-value for a two-tailed hypothesis test with a standardized test statistic of z = 1.64. Decide whether to reject H0 when the level of significance is α = 0.10.
> Find the P-value for a left-tailed hypothesis test with a standardized test statistic of z = -1.71. Decide whether to reject H0 when the level of significance is α = 0.05.
> The P-value for a hypothesis test is P = 0.0745. What is your decision when the level of significance is 1. α = 0.05 and 2. α = 0.10?
> In Example 10, at α = 0.01, is there enough evidence to reject the claim?
> The CEO of the company in Example 9 claims that the mean workday of the company’s mechanical engineers is less than 8.5 hours. A random sample of 25 of the company’s mechanical engineers has a mean workday of 8.2 hours. Assume the population standard dev
> Find the critical values and rejection regions for a two-tailed test with α = 0.08.
> Find the critical value and rejection region for a left-tailed test with α = 0.10.
> Repeat Example 6 using a level of significance of α = 0.01.
> Test the claim about the population mean µ at the level of significance α. Assume the population is normally distributed. Claim: µ ≥ 1475; α = 0.07; σ = 29 Sample statistics: x = 1468, n = 26
> 1. You represent a chemical company that is being sued for paint damage to automobiles. You want to support the claim that the mean repair cost per automobile is less than $650. How would you write the null and alternative hypotheses? How should you inte
> You perform a hypothesis test for each claim. How should you interpret your decision if you reject H0? If you fail to reject H0? 1. A consumer analyst reports that the mean life of a certain type of automobile battery is not 74 months. 2. Ha (Claim): A
> For each claim, state H0 and Ha in words and in symbols. Then determine whether the hypothesis test is a left-tailed test, right-tailed test, or two-tailed test. Sketch a normal sampling distribution and shade the area for the P-value. 1. A consumer ana
> A company specializing in parachute assembly states that its main parachute failure rate is not more than 1%. You perform a hypothesis test to determine whether the company’s claim is false. When will a type I or type II error occur? Which error is more
> Write each claim as a mathematical statement. State the null and alternative hypotheses, and identify which represents the claim. 1. A consumer analyst reports that the mean life of a certain type of automobile battery is not 74 months. 2. An electroni
> The data shown in the table represent the GPAs of randomly selected freshmen, sophomores, juniors, and seniors. At α = 0.05, can you conclude that there is a difference in the means of the GPAs? Assume that the populations of GPAs are norma
> A sales analyst wants to determine whether there is a difference in the mean monthly sales of a company’s four sales regions. Several salespersons from each region are randomly selected and they provide their sales amounts (in thousands
> A biologist claims that the pH levels of the soil in two geographic locations have equal standard deviations. Independent samples from each location are randomly selected, and the results are shown at the left. At α = 0.01, is there enough evidence to re
> A medical researcher claims that a specially treated intravenous solution decreases the variance of the time required for nutrients to enter the bloodstream. Independent samples from each type of solution are randomly selected, and the results are shown
> Find the critical F-value for a two-tailed test when α = 0.01, d.f.N = 2, and d.f.D = 5.
> Test the claim about the population mean µ at the level of significance α. Assume the population is normally distributed. Claim: µ = 40; α = 0.05; σ = 1.97 Sample statistics: x = 39.2, n = 25
> The statement represents a claim. Write its complement and state which is H0 and which is Ha. p ≥ 0.19
> Find the critical F-value for a right-tailed test when α = 0.05, d.f.N = 8, and d.f.D = 20.
> A researcher wants to determine whether age is related to whether or not a tax credit would influence an adult to purchase a hybrid vehicle. A random sample of 1250 adults is selected and the results are classified as shown in the table. At Î&plusm
> The marketing consultant for a travel agency wants to determine whether travel concerns are related to travel purpose. The contingency table shows the results of a random sample of 300 travelers classified by their primary travel concern and travel purpo
> The marketing consultant for a travel agency wants to determine whether certain travel concerns are related to travel purpose. The contingency table shows the results of a random sample of 300 travelers classified by their primary travel concern and trav
