| Question 1 of 17 | 1.0 Points |
Members of the general adult population volunteer an average of 4.2 hours per week.A random sample of 20 female college students and 18 male college students produced the results given in the table below.At the .01 level of significance, is there sufficient evidence to conclude that a difference exists between the mean number of volunteer hours per week for male and female college students? | | Females | Males | | Sample size | 20 | 18 | | Sample mean | 3.8 | 2.5 | | Sample variance | 3.5 | 2.2 | | A.No, because the test value 2.38 is greater than the critical value | | B.No, because the test value 2.38 does not exceed the critical value | | C.No, because the test value 2.90 is greater than the critical value | | D.Yes, because the test value 2.90 is greater than the critical value | Reset Selection | | Question 2 of 17 | 1.0 Points |
Two independent samples of sizes n1 = 50 and n2 =50 are randomly selected from two populations to test the difference between the population means,. The sampling distribution of the sample mean difference,is: | A.approximately normal | | B.chi-squared distributed with 99 degrees of freedom | | C.normally distributed | | D.t - distributed with 98 degrees of freedom | Reset Selection | | Question 3 of 17 | 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 the10% 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. | A.Yes, the test value does not exceed the critical value | | B.Yes, the p-value of this test is greater than 0.10 | | C.No, the p-value of this test is less than 0.10. | | D.No, the test value does not exceed the critical value. | Reset Selection | |
| Question 4 of 17 | 1.0 Points |
In a simple linear regression analysis, the following sum of squares are produced: = 500 = 100 = 400 The proportion of the variation in Y that is explained by the variation in X is: Reset Selection | | Question 5 of 17 | 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 | 1 | 2 | 3 | 4 | 5 | 6 | | Shelf Space | 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 | 15 | 15 | 15 | 20 | 20 | 20 | | Weekly Sales | 2.3 | 2.7 | 2.8 | 2.6 | 2.9 | 3.1 | What is the estimated regression equation? | A. = 1.45 + 0.074x | | B. =2.63 - 0.174x | | C.= 2.63 + 0.724x | | D. =1.45 + 0.724x | Reset Selection | | Question 6 of 17 | 1.0 Points |
In choosing the best-fitting line through a set of points in linear regression, we choose the one with the: | A.smallest sum of squared residuals | | B.largest number of points on the line | | C.largest sum of squared residuals | | D.smallest number of outliers | Reset Selection | | Question 7 of 17 | 1.0 Points |
Data for a sample of 25 apartments in a particular neighborhood are provided in the worksheet Apartments in the Excel workbook Apartments.xlsx. 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. Apartments.xlsx | A. 177.12 + 1.065(size) | | B.177.12 + 0.8500(size) | | C.1.065 + 177.12(size) | | D.197.12 + 2.065(size) | Reset Selection | | Question 8 of 17 | 1.0 Points |
Outliers are observations that | A.render the study useless | | B.lie outside the typical pattern of points | | C.lie outside the sample | | D.disrupt the entire linear trend | Reset Selection | |
| Question 9 of 17 | 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 field researcher is gathering data on the trunk diameters of mature pine and spruce trees in a certain area. The following are the results of his random sampling. Can he conclude, at the 0.10 level of significance, that the average trunk diameter of a pine tree is greater than the average diameter of a spruce tree? | | Pine trees | Spruce trees | | Sample size | 25 | 35 | | Mean trunk diameter (cm) | 55 | 48 | | Sample variance | 100 | 140 | What is the test value for this hypothesis test? Test value: Round your answer to three decimal places. What is the critical value? Critical value: Round your answer to three decimal places. |
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| Question 10 of 17 | 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. Using your estimated regression output, predict the indirect labor expenses for a month in which the company has 31 direct labor hours. Place your answer, rounded to1 decimal place, in the blank. Do notuse any stray punctuation marks or a dollar sign. For example, 458.9 would be a legitimate entry. | | Question 11 of 17 | 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. Approximately what percentage of the variation in indirect laborexpenses is explained by the regression model you derived? Place your answer, rounded to1 decimal place, in the blank. Do notuse any stray punctuation marks or apercentage sign. For example, 78.9 would be a legitimate entry. | |
| Question 12 of 17 | 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. 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 byits 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. Suppose, using a 10% level of significance,you wish to know if there is 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. That is supposeyou wish to test H0: versus H1: Assuming that the amounts spent by male and female charge customers at Q-Mart are normally distributed, based on the procedure advocated by Bluman, what is the test value that you would use to conduct this test of hypothesis? Place your answer, rounded to 3 decimal places, in the blank. For example, 0.123 would be a legitimate entry. | | Question 13 of 17 | 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 test 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. | |
| Question 14 of 17 | 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. Researchers conducted an experiment to measure the effect of a drug on improving the quality of sleep as determined by how many more minutes of REM sleep were measured for each participant. One group of participants were given the experimental drug; the other (control) group was given a placebo. Does the evidence indicate that the drug improved the amount of REM sleep at a 0.01 level of significance? Answer each of the following parts. | Experimental group | Control group | | sample size | 35 | 50 | | mean sleep improvement | 12.8 | 9.1 | | sample variance | 56.3 | 61.2 | What is the test value for this hypothesis test? Answer: Round your answer to two decimal places. What is the P-value for this hypothesis test? Answer: Round your answer to three decimal places. What is the conclusion of this hypothesis test? Choose one. 1. There is sufficient evidence to show that the experimental drug improved the quality of sleep. 2. There is not sufficient evidence to show that the experimental drug improved the quality of sleep. 3. There is sufficient evidence to show that the quality of sleep is different for the experimental drug than for the control drug. 4. There is not sufficient evidence to show that the control drug decreased the quality of sleep. Answer: Enter only a 1, 2, 3 or 4 for your answer. |
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| Question 15 of 17 | 1.0 Points |
When the necessary conditions are met, a two-tail test is being conducted to test the difference between two population proportions. The two sample proportions are= 0.35 and= 0.42, and the standard error of the sampling distribution ofis 0.054. The calculated value of the test statistic is 1.2963. Reset Selection |
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| Question 16 of 17 | 1.0 Points |
In a simple linear regression problem, if the coefficient of determination is 0.95, this means that 95% of the variation in the explanatory variable X can be explained by regression. Reset Selection | | Question 17 of 17 | 1.0 Points |
A negative relationship between an explanatory variable X and a response variable Y means that as X increases, Y decreases, and vice versa. Reset Selection | |
