of 8 Question 1 of 17 1.0 Points 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 .10 level of significance, that the average trunk diameter of a pine tree is greater than the average diameter of a spruce tree? Sample size Mean trunk diameter (cm) Sample variance Pine trees 40 45 100 Spruce trees 70 39 150 A. The data do not support the claim because the test value 1.29 is greater than 1.28. B.The data support the claim because the test value 2.78 is greater than 1.28. C.The data do not support the claim because the test value 1.29 is less than 1.64. D. The data support the claim because the test value 2.78 is greater than 1.64. Reset Selection Question 2 of 17 1.0 Points Some defendants in criminal proceedings plead guilty and are sentenced without a trial, whereas others who plead innocent are subsequently found guilty and then are sentenced. In recent years, legal scholars have speculated as to whether sentences of those who plead guilty differ in severity from sentences for those who plead innocent and are subsequently judged guilty. Consider the data given below on defendants accused of robbery, all of whom, by the way, had previous prison records. At the .01 level of significance, do these data suggest that the proportion of all defendants in these circumstances who plead guilty and are sent to prison differs from the proportion who are sent to prison after pleading innocent and being found guilty? Plea Number judged guilty Number sentenced to prison Sample proportion Guilty n1 = 191 x1 = 101 Not Guilty n2 = 64 x2 = 56 .529 .875 A.Yes, because the test value -4.94 is outside the interval (-2.58, 2.58) B.No, because the test value -4.94 is outside the interval (-1.96, 1.96) C.Yes, because the test value 2.58 is inside the interval (-4.94, 4.94) D.No, because the test value -1.96 is inside the interval (-2.58, 2.58) Reset Selection Question 3 of 17 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 = 3.252 B.t = 0.151 C.z = 0.081 D.z = 0.455 Reset Selection Part 2 of 8 Question 4 of 17 1.0 Points An agent for a residential real estate company in a large city would like to be able to predict the monthly rental cost of apartments based on the size of the apartment. Data for a sample of 25 apartments in a particular neighborhood are provided in the worksheet Apartments in the Excel workbook Apartments.xlsx. Apartments.xlsx At the .05 level of significance determine if the correlation between rental cost and apartment size is significant. A.No, there is not a statistically significant linear relationship between monthly rental cost and apartment size, because the sample correlation coefficient is less than .95. B.Yes, there is a statistically significant linear relationship between monthly rental cost and apartment size, because the sample correlation coefficient 0.85 exceeds 0.50. C.Yes, there is a statistically significant linear relationship between monthly rental cost and apartment size, because the p-value for this test is less than .0001. D.Yes, there is a statistically significant linear relationship between monthly rental cost and apartment size, because the t-test value, 7.74, is greater than the critical value 1.96. Reset Selection Question 5 of 17 1.0 Points In regression analysis, the variable we are trying to explain or predict is called the A.residual variable B.independent variable C.dependent variable D.regression variable Reset Selection Question 6 of 17 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.a curved relationship among the variables C.the strength of the linear relationship between pairs of variables D.the magnitude of difference between two variables Reset Selection Question 7 of 17 1.0 Points In a simple linear regression analysis, the following sum of squares are produced: = 400 = 80 = 320 The proportion of the variation in Y that is explained by the variation in X is: A.80 % B.20 % C.25 % D.50 % Reset Selection Question 8 of 17 1.0 Points A linear regression analysis produces the equation y = 5.32 + (-0.846)x Which of the following statements must be true? A.As x increases, y increases, and the correlation coefficient must be positive. B.As x increases, y decreases, and the correlation coefficient must be positive. C.As x increases, y decreases, and the correlation coefficient must be negative. D.As x increases, y increases, and the correlation coefficient must be negative. Reset Selection Part 3 of 8 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 30 35 Mean trunk diameter (cm) 45 39 Sample variance 120 140 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: Part 4 of 8 - Round your answer to three decimal places. 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. Approximately what percentage of the variation in indirect labor expenses is explained by the regression model you derived? Place your answer, rounded to 1 decimal place, in the blank. Do not use any stray punctuation marks or a percentage sign. For example, 78.9 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. What values for the intercept (a) and slope (b) do you obtain? Place your answers, rounded to 3 decimal places, in the blanks provided. Do not use any stray punctuation marks. For example, 34.567 would be a legitimate entry. intercept (a) = slope(b) = Part 5 of 8 - 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. 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/are the critical value you would use to conduct such a test of hypothesis? Place your answer, rounded to 2 decimal places, in the blank. If there are two critical values, place only the positive value in the blank. For example, 2.34 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. 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: n1 = 21, s1 = .849, n2 = 21, s2 = .529. If you follow Bluman's advice and place the larger variance in the numerator, what is the test value associated with this test of hypothesis? Place your answer, rounded to 3 decimal places, in the blank. For example, 3.456 would be a legitimate entry. Part 6 of 8 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. Part 7 of 8 Question 15 of 17 1.0 Points When testing the equality of two population variances, the test statistic is the ratio of the population variances; namely . True False Reset Selection Part 8 of 8 Question 16 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. True False Reset Selection Question 17 of 17 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 Reset Selection