1 of 23 1.0 Points A company operates four machines during three shifts each day. From production records, the data in the table below were collected. At the .05 level of significance test to determine if the number of breakdowns is independent of the shift. Machine Shift A B C D 1 41 20 12 16 2 31 11 9 14 3 15 17 16 10 A.The number of breakdowns is dependent on the shift, because the test value 11.649 is less than the critical value of 12.592. B.The claim that the number of breakdowns is independent of the shift cannot be rejected, because the test value 11.649 is less than the critical value of 12.592. C.The number of breakdowns is dependent on the shift, because the p-value is .07. D.The number of breakdowns is independent of the shift, because the test value 12.592 is greater than the critical value of 11.649. Reset Selection Question 2 of 23 1.0 Points The data presented in the table below resulted from an experiment in which seeds of 5 different types were planted and the number of seeds that germinated within 5 weeks after planting was recorded for each seed type. At the .01 level of significance, is the proportion of seeds that germinate dependent on the seed type? Seed Type Observed Frequencies Germinated Failed to Germinate 1 31 7 2 57 33 3 87 60 4 52 44 5 10 19 A.Yes, because the test value 16.86 is greater than the critical value of 13.28 B.Yes, because the test value 16.86 is less than the critical value of 14.86 C.No, because the test value 16.86 is greater than the critical value of 13.28 D.No, because the test value 13.28 is less than the critical value of 16.86 Reset Selection Part 2 of 16 Question 3 of 23 1.0 Points ____________ is/are especially helpful in identifying outliers. A.Regression analysis B.Scatterplots C.Linear regression D.Normal curves Reset Selection Question 4 of 23 1.0 Points The marketing manager of a large supermarket chain would like to use shelf space to predict the sales of pet food. For a random sample of 12 similar stores, she gathered the following information regarding the shelf space, in feet, devoted to pet food and the weekly sales in hundreds of dollars. . Store Shelf Space 1 2 3 4 5 6 5 5 5 10 10 10 Weekly Sales 1.6 2.2 1.4 1.9 2.4 2.6 Store 7 8 9 10 11 12 Shelf Space Weekly Sales 15 15 15 20 20 20 2.3 2.7 2.8 2.6 2.9 3.1 Is the correlation between weekly sales and shelf space significant at the .01 level of significance? A. Yes, the computed t-test statistic is less than the critical value. B.Yes, the value of the test statistic does not exceed the critical value. C.No, the sample correlation coefficient does not exceed the critical value. D.Yes, the p-value of the test for significance is less than .01. Reset Selection Question 5 of 23 1.0 Points Correlation is a summary measure that indicates: A.the rate of change in Y for a one unit change in X B.the magnitude of difference between two variables C.a curved relationship among the variables D.the strength of the linear relationship between pairs of variables Reset Selection Part 3 of 16 Question 6 of 23 1.0 Points A pharmaceutical company is testing the effectiveness of a new drug for lowering cholesterol. As part of this trial, they wish to determine whether there is a difference between the effectiveness for women and for men. Assume = 0.05. What is the test value? Women Men Sample size 50 80 Mean effect 7 6.95 Sample variance 3 4 A.t = 0.151 B.z = 0.081 C.t = 3.252 D.z = 0.455 Reset Selection Question 7 of 23 1.0 Points Two teams of workers assemble automobile engines at a manufacturing plant in Michigan. A random sample of 145 assemblies from team 1 shows 15 unacceptable assemblies. A similar random sample of 125 assemblies from team 2 shows 8 unacceptable assemblies. Is there sufficient evidence to conclude, at the 10% significance level, that the two teams differ with respect to their proportions of unacceptable assemblies? A.Yes, since the p-value is greater than 0.10 B.No, since the test value exceeds the critical value C.No, since the test value does not exceed the critical value D.No, since the p-value is less than 0.10 Reset Selection Part 4 of 16 Question 8 of 23 1.0 Points In an article appearing in Today's Health a writer states that the average number of calories in a serving of popcorn is 75. To determine if the average number of calories in a serving of popcorn is different from 75, a nutritionist selected a random sample of 20 servings of popcorn and computed the sample mean number of calories per serving to be 78 with a sample standard deviation of 7. At the a = .05 level of significance, does the nutritionist have enough evidence to reject the writer's claim? A.No B.Yes C.Cannot Determine Reset Selection Question 9 of 23 1.0 Points In an article appearing in Today's Health a writer states that the average number of calories in a serving of popcorn is 75. To determine if the average number of calories in a serving of popcorn is different from 75, a nutritionist selected a random sample of 20 servings of popcorn and computed the sample mean number of calories per serving to be 78 with a sample standard deviation of 7. State the null and alternative hypotheses. A.H0: 75, H1: > 75 B.H0: 75, H1: < 75 C.H0: = 75, H1: > 75 D.H0: = 75, H1: 75 Reset Selection Question 10 of 23 1.0 Points A null hypothesis can only be rejected at the 5% significance level if and only if: A.the null hypotheses includes sampling error B.the null hypothesis is biased C.a 95% confidence interval does not include the hypothesized value of the parameter D.a 95% confidence interval includes the hypothesized value of the parameter Reset Selection Part 5 of 16 Question 11 of 23 1.0 Points A researcher wishes to know, with 98% confidence, the percentage of women who wear shoes that are too small for their feet. A previous study conducted by the Academy of Orthopedic Surgeons found that 80% of women wear shoes that are too small for their feet. If the researcher wants her estimate to be within 3% of the true proportion, how large a sample is necessary? A.966 B.683 C.183 D.484 Reset Selection Question 12 of 23 1.0 Points In order to be accepted into a top university, applicants must score within the top 5% on the SAT exam. Given that SAT test scores are normally distributed with a mean of 1000 and a standard deviation of 200, what is the lowest possible score a student needs to qualify for acceptance into the university? A.1330 B.1400 C.1250 D.1100 Reset Selection Part 6 of 16 Question 13 of 23 1.0 Points If Z is a standard normal random variable, the area between z = 0.0 and z =1.30 is 0.4032, while the area between z = 0.0 and z = 1.50 is 0.4332. What is the area between z = -1.30 and z = 1.50? A.0.8364 B.0.0968 C.0.0668 D.0.0300 Reset Selection Part 7 of 16 Question 14 of 23 1.0 Points Which term is NOT synonymous with the expected value of a discrete probability distribution? A. B.variance C.theoretical average D.mean Reset Selection Part 8 of 16 Question 15 of 23 1.0 Points The result of tossing a coin once will be either head or tail. Let A and B be the events of observing head and tail, respectively. The events A and B are: A.independent B.conditional C.mutually exclusive D.unilateral Reset Selection Part 9 of 16 Question 16 of 23 3.0 Points Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A sport preference poll yielded the following data for men and women. Use a 5% significance level and test to determine if sport preference and gender are independent. Sport Preferences of Men and Women Basketball Football Soccer Men 20 25 30 75 Women 18 12 15 45 38 37 45 120 What is the test value for this hypothesis test? Answer: Round your answer to two decimal places. What is the critical value for this hypothesis test? Answer: Round your answer to two decimal places. What is the conclusion for this hypothesis test? Choose one. 1. There is sufficient evidence to support the claim that one's sport preference is dependent on one's gender. 2. There is not sufficient evidence to support the claim that one's sport preference is dependent on one's gender. Answer: Enter only a 1 or 2 for your answer. Part 10 of 16 Question 17 of 23 1.0 Points Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Data for a sample of 25 apartments in a particular neighborhood are provided in the worksheet Apartments in the Excel workbook Apartments.xlsx. Using the estimated regression equation found by using size as the predictor variable, find a point estimate for the average monthly rent for apartments having 1,000 square feet of space. Place your answer, rounded to the nearest whole dollar, in the blank. When entering your answer do not use any labels or symbols. Simply provide the numerical value. For example, 123 would be a legitimate entry. Apartments.xlsx Part 11 of 16 Question 18 of 23 1.0 Points Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. An investor wants to compare the risks associated with two different stocks. One way to measure the risk of a given stock is to measure the variation in the stock's daily price changes. In an effort to test the claim that the variance in the daily stock price changes for stock 1 is different from the variance in the daily stock price changes for stock 2, the investor obtains a random sample of 21 daily price changes for stock 1 and 21 daily price changes for stock 2. The summary statistics associated with these samples are: n 1 = 21, s1 = .848, n2 = 21, s2 = .529. If you follow Bluman's advice and place the larger variance in the numerator when computing the test value, at the .05 level of significance, what is the critical value associated with this test of hypothesis? Place your answer, rounded to 2 decimal places, in the blank. For example, 3.45 would be a legitimate entry. Part 12 of 16 Question 19 of 23 1.0 Points Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Suppose that the average weekly earnings for employees in general automotive repair shops is $450, and that the standard deviation for the weekly earnings for such employees is $50. A sample of 100 such employees is selected at random. Find the probability that the mean of the sample is between $445 and $455. Place your answer, rounded to 4 decimal places, in the blank. For example, 0.2345 would be a legitimate entry. Part 13 of 16 Question 20 of 23 1.0 Points Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Senior management of a consulting services firm is concerned about a growing decline in the firm's weekly number of billable hours. The firm expects each professional employee to spend at least 40 hours per week on work. In an effort to understand this problem better, management would like to estimate the standard deviation of the number of hours their employees spend on workrelated activities in a typical week. Rather than reviewing the records of all the firm's full-time employees, the management randomly selected a sample of size 51 from the available frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively. Construct a 90% confidence interval for the standard deviation of the number of hours this firm's employees spend on work-related activities in a typical week. Place your LOWER limit, in hours, rounded to 1 decimal place, in the first blank. For example, 6.7 would be a legitimate entry. Place your UPPER limit, in hours, rounded to 1 decimal place, in the second blank. For example, 12.3 would be a legitimate entry. Part 14 of 16 Question 21 of 23 1.0 Points Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Suppose that the probability that a new medication will cause a bad side effect is 0.03. If this medication is given to 150 people, what is the probability that more than three of them will experience a bad side effect? Place your answer, rounded to 4 decimal places, in the blank. For example, 0.1776 would be a legitimate answer. Part 15 of 16 Question 22 of 23 1.0 Points Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For sci- entific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. The ABC battery company claims that their batteries last at least 100 hours, on average. Your experience with their batteries has been somewhat different, so you decide to conduct a test to see if the company's claim is true. You believe that the mean life is actually less than the 100 hours the company claims. You decide to collect data on the average battery life (in hours) of a random sample of n = 20 batteries. Some of the information related to the hypothesis test is presented below. Test of H0: 100 versus H1: Sample mean 98.5 Std error of mean 0.777 100 Assuming the life length of batteries is normally distributed, if you wish to conduct this test using a .05 level of significance, what is the critical value that you should use? Place your answer, rounded to 3 decimal places in the blank. For example, -1.234 would be a legitimate entry. Part 16 of 16 Question 23 of 23 1.0 Points Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. If a set of six books is to be placed on a shelf, in how many ways can the six books be arranged? Place your answer in the blank. Do not use any decimal places or commas. For example, 45 would be a legitimate entry