MATH 302 QUIZ 5-QUESTIONS AND ANSWERS

Quiz 5 MATH302 Part 1 of 8 - 3.0/ 3.0 Points Question 1 of 17 1.0/ 1.0 Points Q-Mart is interested in comparing its male and female customers. Q-Mart would like to know if the amount of money spent by its female charge customers differs, on average, from the amount spent by its male charge customers. To answer this question, an analyst collected random samples of 25 female customers and 22 male customers. Based on these samples, on average, the 25 women charge customers spent $102.23 and the 22 men charge customers spent $86.46. Moreover, the sample standard deviation of the amount charged by the 25 women was $93.393, and the sample standard deviation of the amount charged by the 22 men was $59.695. Using the procedure advocated by Bluman, at the 10% level of significance, is there sufficient evidence for Q-Mart to conclude that, on average, the amount spent by women charge customers differs from the amount spent by men charge customers. Question 2 of 17 1.0/ 1.0 Points A researcher hypothesizes that the variation in the amount of money spent on business dinners is greater than the variation of the amount of money spent on lunches. The variance of nine business dinners was $6.12 and the variance of 12 business lunches was $0.87. What is the test value? Question 3 of 17 1.0/ 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 α = 0.05. What is the test value? Women Men Sample size 50 80 Mean effect 7 6.95 Sample variance 3 4 Part 2 of 8 - 5.0/ 5.0 Points Question 4 of 17 1.0/ 1.0 Points The correlation value ranges from Question 5 of 17 1.0/ 1.0 Points Outliers are observations that Question 6 of 17 1.0/ 1.0 Points A single variable X can explain a large percentage of the variation in some other variable Y when the two variables are: Question 7 of 17 1.0/ 1.0 Points is/are especially helpful in identifying outliers. A.Normal curves B.Linear regression C.Scatterplots D.Regression analysis Answer Key: C Question 8 of 17 1.0/ 1.0 Points Data for a sample of 25 apartments in a particular neighborhood are provided in the worksheet Apartments in the Excel workbook A. Using that data, find the estimated regression equation which can be used to estimate the monthly rent for apartments in this neighborhood using size as the predictor variable. A Part 3 of 8 - 1.0/ 2.0 Points Question 9 of 17 1.0/ 2.0 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 business major wants to determine whether the variation in advertising costs of hair salons is different from the variation in advertising costs of nail salons. He surveys several businesses and finds the standard deviation in monthly advertising costs is $23 for 12 hair salons, and $43 for 8 nail salons. What is the test value for this hypothesis test? Test value: 3.50 Round your answer to two decimal places. At the 0.05 level of significance, what is the critical value? Critical value: 3.28 Round your answer to two decimal places. Answer Key: 3.50, 3.76 Feedback: This is a test of the difference between two variances. The test value F is found using the formula on page 509: This is a two-tail test with alpha = 0.05. From Table H for alpha = 0.05/2 = 0.025 with dfN = 7 and dfD = 11, the critical value is 3.76. Since the F test value is less than the critical value, there is not sufficient evidence to show that the variation in ad costs for hair salons is different from the ad costs for nail salons. Part 4 of 8 - 2.0/ 2.0 Points Question 10 of 17 1.0/ 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. The marketing manager of a large supermarket chain would like to determine the effect of shelf space (in feet) on the weekly sales of international food (in hundreds of dollars). A random sample of 12 equal –sized stores is selected, with the following results: Store Shelf Space(X) Weekly Sales(Y) 1 10 2.0 2 10 2.6 3 10 1.8 4 15 2.3 5 15 2.8 6 15 3.0 7 20 2.7 8 20 3.1 9 20 3.2 10 25 3.0 11 25 3.3 12 25 3.5 Based on these data, what are the least squares regression coefficients of the Y-intercept (a) and slope (b)? Place your answers, rounded to 3 decimal places , in the blanks provided. a = 1.480 b = 0.074 Answer Key: 1.480, 0.074 Question 11 of 17 1.0/ 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. A company has observed that there is a linear relationship between indirect labor expense (ILE) , in dollars, and direct labor hours (DLH). Data for direct labor hours and indirect labor expense for 18 months are given in the file ILE_and_DLH.xlsx Treating ILE as the response variable, use regression to fit a straight line to all 18 data points. Based on your results, If direct labor hours (DLH) increases by one hour, the indirect labor expense (ILE), on average, increases by approximately how much? Place your answer, rounded to 2 decimal places, in the blank. Do not use any stray punctuation marks or a dollar sign. For example, 34.56 would be a legitimate entry. 15.26 Answer Key: 15.26 Part 5 of 8 - 0.0/ 2.0 Points Question 12 of 17 0.0/ 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. 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. If you are interested in determining if there is sufficient evidence to conclude, at the 10% significance level, that the two teams differ with respect to their proportions of unacceptable assemblies, what is the test value you would use to conduct such a test of hypothesis? Place your answer, rounded to 2 decimal places, in the blank. For example, 2.34 would be a legitimate entry. 1.65 Answer Key: 1.15|1.16 Question 13 of 17 0.0/ 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. Are America's top chief executive officers (CEOs) really worth all that money? One way to answer this question is to look at the annual company percentage increase in revenue versus the CEO's annual percentage salary increase in that same company. Suppose that a random sample of companies yielded the following data: percent change for corporation 15 12 3 12 28 6 8 2 percent change for CEO 6 17 -4 12 32 -1 7 2 Do these data indicate that the population mean percentage increase in corporate revenue is greater than the population mean percentage increase in CEO salary? Use a 5% level of significance. What is the critical value that you would use to conduct this test of hypothesis? Place your answer, rounded to 3 decimal places, in the blank. For example, 2.345 would be a legitimate entry. 1.010 Answer Key: 1.895 Part 6 of 8 - 3.0/ 3.0 Points Question 14 of 17 3.0/ 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 professor gives an exam for which there are two versions, A and B. Each student in the class is given one randomly selected version of the exam. After the exam, the professor wishes to determine if there is a difference in the level of difficulty of the two versions by determining if there is a significant difference in the mean scores. Assume α = 0.05. Version A Version B Sample size 45 65 Mean score 8.8 8.2 Sample variance 2.6 2.4 What is the test value for this hypothesis test? Answer: 1.95 Round your answer to two decimal places. What is/are the critical value(s) for this hypothesis test? If there are two critical values, give only the positive value. Answer: 2.01 Round your answer to two decimal places. What is the conclusion for this hypothesis test? Choose one. 1. There is not sufficient evidence to show that one version of the exam is more difficult than the other. 2. There is sufficient evidence to show that one version of the exam is more difficult than the other. Answer: 1 Enter only a 1 or 2 for your answer. Answer Key: 1.95, 2.01|2.02, 1 Part 7 of 8 - 0.0/ 1.0 Points Question 15 of 17 0.0/ 1.0 Points When testing the equality of two population variances, the test statistic is the ratio of the population variances; namely . True False Answer Key: False Part 8 of 8 - 2.0/ 2.0 Points Question 16 of 17 1.0/ 1.0 Points A simple linear regression equation is given by y' = 5 + 3x. The predicted value of Y when X = 3 is 5. True False Answer Key: False Question 17 of 17 1.0/ 1.0 Points In a simple regression analysis, if the standard error of estimate sest = 15 and the number of observations n = 10, then the sum of the residuals squared must be 120. True False Answer Key: False