Use the regression equation found in Try It Yourself 1 to predict a student’s final grade for each set of conditions.
1. A student has a midterm exam score of 89 and misses 1 class.
2. A student has a midterm exam score of 78 and misses 3 classes.
3. A student has a midterm exam score of 83 and misses 2 classes
> 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
> A researcher claims that the number of different-colored candies in bags of peanut M&€™s® is uniformly distributed. To test this claim, you randomly select a bag that contains 180 peanut M&M’s®. T
> A sociologist claims that the age distribution for the residents of a city is different from the distribution 10 years ago. The distribution of ages 10 years ago is shown in the table at the left. You randomly select 400 residents and record the age of e
> The tax preparation company in Example 1 decides it wants a larger sample size, so it randomly selects 500 adults. Find the expected frequency for each tax preparation method for n = 500.
> A statistics professor wants to determine how students’ final grades are related to the midterm exam grades and number of classes missed. The professor selects 10 students and obtains the data shown in the table. Use technology to find
> Using the results of Example 2, construct a 95% prediction interval for the carbon dioxide emissions when the gross domestic product is $4 trillion. What can you conclude?
> State whether each standardized test statistic z allows you to reject the null hypothesis. Explain your reasoning. a. z = 1.98 b. z = -1.89 c. z = 1.65 d. z = -1.99 -3 -2 -1 0 1 /2 3 -20= -1.96 20= 196
> The correlation coefficient for the Old Faithful data is r ≈ 0.979. Find the coefficient of determination. What does this tell you about the explained variation of the data about the regression line? about the unexplained variation?
> Use technology to find the equation of the regression line for the salaries and average attendances at home games for the teams in Major League Baseball listed on page 469. From page 469: Salary (in millions of dollars) 78.4 75.0 153.7 218.7 176.1 1
> Find the equation of the regression line for the number of years out of school and annual contribution data used in Try It Yourself 4 in Section 9.1.
> In Try It Yourself 5, you calculated the correlation coefficient of the salaries and average attendances at home games for the teams in Major League Baseball to be r ≈ 0.775. Test the significance of this correlation coefficient. Use α = 0.01.
> In Try It Yourself 4, you calculated the correlation coefficient of the number of years out of school and annual contribution data to be r ≈ -0.908. Is the correlation coefficient significant? Use α = 0.01.
> Use technology to calculate the correlation coefficient for the data on page 469 on the salaries and average attendances at home games for the teams in Major League Baseball. Interpret the result in the context of the data. From page 469: Salary (i
> Calculate the correlation coefficient for the number of years out of school and annual contribution data in Try It Yourself 1. Interpret the result in the context of the data. Annual contribution Number of years out of school, x (in 1000s of $), y 12
> Consider the data on page 469 on the salaries and average attendances at home games for the teams in Major League Baseball. Use technology to display the data in a scatter plot. Describe the type of correlation. From page 469: Salary (in millions o
> State whether each standardized test statistic z allows you to reject the null hypothesis. Explain your reasoning. a. z = -1.301 b. z = 1.203 c. z = 1.280 d. z = 1.286 123 Z0 = 1.285
> A researcher conducts a study to determine whether there is a linear relationship between a person’s height (in inches) and pulse rate (in beats per minute). The data are shown in the table below. Display the data in a scatter plot and
> A director of alumni affairs at a small college wants to determine whether there is a linear relationship between the number of years alumni have been out of school and their annual contributions (in thousands of dollars). The data are shown in the table
> Consider the results of the study discussed on page 417. At a = 0.05, can you support the claim that the proportion of yoga users with incomes of $20,000 to $34,999 is less than the proportion of non-yoga users with incomes of $20,000 to $34,999? From p
> Consider the results of the study discussed on page 417. At α = 0.05, can you support the claim that there is a difference between the proportion of yoga users who are 40- to 49-year-olds and the proportion of non-yoga users who are 40- to
> A medical researcher wants to determine whether a drug changes the body’s temperature. Seven test subjects are randomly selected, and the body temperature (in degrees Fahrenheit) of each is measured. The subjects are then given the drug
> A shoe manufacturer claims that athletes can decrease their times in the 40-yard dash using the manufacturer’s training shoes. The 40-yard dash times of 12 randomly selected athletes are measured. After the athletes have used the shoes for 8 months, thei
> A manufacturer claims that the mean driving cost per mile of its minivans is less than that of its leading competitor. You conduct a study using 34Â randomly selected minivans from the manufacturer and 38 from the leading competitor. The resul
> The annual earnings of 25 people with a high school diploma and 16 people with an associate’s degree are shown at the left. Can you conclude that there is a difference in the mean annual earnings based on level of education? Use Î
> A travel agency claims that the average daily cost of meals and lodging for vacationing in Alaska is greater than the average daily cost in Colorado. The table at the left shows the results of a random survey of vacationers in each state. The two samples
> A survey indicates that the mean annual wages for forensic science technicians working for local and state governments are $60,680 and $59,430, respectively. The survey includes a randomly selected sample of size 100 from each government branch. Assume t
> Find the critical value(s) and rejection region(s) for the type of z-test with level of significance α. Include a graph with your answer. Two-tailed test, α = 0.12
> Classify each pair of samples as independent or dependent. 1. Sample 1: Systolic blood pressures of 30 adult females Sample 2: Systolic blood pressures of 30 adult males 2. Sample 1: Midterm exam scores of 14 chemistry students Sample 2: Final exam s
> A company that offers dieting products and weight loss services claims that the variance of the weight losses of their users is 25.5. A random sample of 13 users has a variance of 10.8. At α = 0.10, is there enough evidence to reject the company’s claim?
> A police chief claims that the standard deviation of the lengths of response times is less than 3.7 minutes. A random sample of 9 response times has a standard deviation of 3.0 minutes. At α = 0.05, is there enough evidence to support the police chief’s
> A bottling company claims that the variance of the amount of sports drink in a 12-ounce bottle is no more than 0.40. A random sample of 31 bottles has a variance of 0.75. At α = 0.01, is there enough evidence to reject the company’s claim? Assume the pop
> A researcher claims that 67% of U.S. adults believe that doctors prescribing antibiotics for viral infections for which antibiotics are not effective is a significant cause of drug-resistant superbugs. (Superbugs are bacterial infections that are resista
> A researcher claims that more than 90% of U.S. adults have access to a smartphone. In a random sample of 150 adults, 87% say they have access to a smartphone. At α = 0.01, is there enough evidence to support the researcher’s claim?
> Another department of motor vehicles office claims that the mean wait time is at most 18 minutes. A random sample of 12 people has a mean wait time of 15 minutes with a standard deviation of 2.2 minutes. At α = 0.05, test the office’s claim. Assume the p
> Find the critical value(s) and rejection region(s) for the type of z-test with level of significance α. Include a graph with your answer. Two-tailed test, α = 0.02
> The company in Example 5 claims that the mean conductivity of the river is 1890 milligrams per liter. The conductivity of a water sample is a measure of the total dissolved solids in the sample. You randomly select 39 water samples and measure the conduc
> An industry analyst says that the mean age of a used car sold in the last 12 months is less than 4.1 years. A random sample of 25 used cars sold in the last 12 months has a mean age of 3.7 years and a standard deviation of 1.3 years. Is there enough evid
> Find the critical values -t0 and t0 for a two-tailed test with α = 0.05 and n = 16.
> Find the critical value t0 for a right-tailed test with α = 0.10 and n = 9.
> Find the critical value t0 for a left-tailed test with α = 0.01 and n = 14.
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test or a t-test. Explain your reasoning. c. Find the critical value(s) and identify the rejection r
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test or a t-test. Explain your reasoning. c. Find the critical value(s) and identify the rejection r
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test or a t-test. Explain your reasoning. c. Find the critical value(s) and identify the rejection r
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test or a t-test. Explain your reasoning. c. Find the critical value(s) and identify the rejection r
> Find the critical value(s) and rejection region(s) for the type of z-test with level of significance α. Include a graph with your answer. Right-tailed test, α = 0.08
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test, a t-test, or a chi-square test. Explain your reasoning. c. Choose one of the options. Option
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test, a t-test, or a chi-square test. Explain your reasoning. c. Choose one of the options. Option
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test, a t-test, or a chi-square test. Explain your reasoning. c. Choose one of the options. Option
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test, a t-test, or a chi-square test. Explain your reasoning. c. Choose one of the options. Option
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test, a t-test, or a chi-square test. Explain your reasoning. c. Choose one of the options. Option
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test, a t-test, or a chi-square test. Explain your reasoning. c. Choose one of the options. Option
> a. Identify the claim and state H0 and Ha. b. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and whether to use a z-test, a t-test, or a chi-square test. Explain your reasoning. c. Choose one of the options. Option
> In each exercise, a. identify the claim and state H0 and Ha, b. find the critical value and identify the rejection region, c. find the test statistic, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision i
> In each exercise, a. identify the claim and state H0 and Ha, b. find the critical value and identify the rejection region, c. find the test statistic, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision i
> In each exercise, a. identify the claim and state H0 and Ha, b. find the critical value and identify the rejection region, c. find the test statistic, d. decide whether to reject or fail to reject the null hypothesis, and e. interpret the decision i