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STATS Problems Assignment

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Question;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? Pine trees Spruce treesSample size 40 70Mean trunk diameter (cm) 45 39Sample variance 100 150 A.The data support the claim because the test value 2.78 is greater than 1.28. B. The data do not support the claim because the test value 1.29 is greater than 1.28. C. The data support the claim because the test value 2.78 is greater than 1.64. D.The data do not support the claim because the test value 1.29 is less than 1.64. Question 2 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 MalesSample size 20 18Sample mean 3.8 2.5Sample 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 Question 3 of 17 1.0 PointsMultiple myeloma or blood plasma cancer is characterized by increased blood vessel formulation in the bone marrow that is a prognostic factor in survival. One treatment approach used for multiple myeloma is stem cell transplantation with the patient?s own stem cells. The following data represent the bone marrow microvessel density for a sample of 7 patients who had a complete response to a stem cell transplant as measured by blood and urine tests. Two measurements were taken: the first immediately prior to the stem cell transplant, and the second at the time of the complete response.Patient 1 2 3 4 5 6 7Before 158 189 202 353 416 426 441After 284 214 101 227 290 176 290Suppose you wanted to conduct a test of hypothesis to determine if there is sufficient evidence to conclude that the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant? What is the p-value associated with the test of hypothesis you would conduct? A.p =.057493 B.p =.114986 C.p =.942597 D.p =.885014 Question 4 of 17 1.0 PointsAn 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. At the.05 level of significance determine if the correlation between rental cost and apartment size is significant. A.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. 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.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. D.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. Question 5 of 17 1.0 PointsOutliers are observations that A.disrupt the entire linear trend B.render the study useless C.lie outside the typical pattern of points D.lie outside the sample Question 6 of 17 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 6Shelf Space 5 5 5 10 10 10Weekly Sales 1.6 2.2 1.4 1.9 2.4 2.6Store 7 8 9 10 11 12Shelf Space 15 15 15 20 20 20Weekly Sales 2.3 2.7 2.8 2.6 2.9 3.1What is the estimated regression equation?a. y^= 2.63 + 0.724xb. y^= 1.45 + 0.724xc. y^= 2.63 - 0.174xd. y^= 1.45 + 0.074xQuestion 7 of 17 1.0 PointsA correlation value of zero indicates. A.a weak linear relationship B.a perfect linear relationship C.no linear relationship D.a strong linear relationship Question 8 of 17 1.0 PointsThe regression line y' = -3 + 2.5 X has been fitted to the data points (28, 60), (20, 50), (10, 18), and (25, 55). The sum of the squared residuals will be: A.16.00 B.94.25 C.49.00 D.20.25 Question 9 of 17 2.0 PointsAccepted 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 treesSample size 20 30Mean trunk diameter (cm) 45 39Sample variance 100 150What 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.Question 10 of 17 1.0 PointsAccepted 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 2.02 10 2.63 10 1.84 15 2.35 15 2.86 15 3.07 20 2.78 20 3.19 20 3.210 25 3.011 25 3.312 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 = ________ b = ___________Question 11 of 17 1.0 PointsAccepted 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 2.02 10 2.63 10 1.84 15 2.35 15 2.86 15 3.07 20 2.78 20 3.19 20 3.210 25 3.011 25 3.312 25 3.5 Using the equation of the regression line for these data, predict the average weekly sales (in hundreds of dollars) of international food for stores with 13 feet of shelf space for international food. Place your answer, rounded to 3 decimal places, in the blank. Do not use a dollar sign. For example, 2.345 would be a legitimate entry. _____________ Part 5 of 8 -Question 12 of 17 1.0 PointsAccepted 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 p-value associated with such a test of hypothesis? Place your answer, rounded to 4 decimal places, in the blank. For example,.0123 would be a legitimate entry. Question 13 of 17 1.0 PointsAccepted 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 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. 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 suppose you wish to testH0: versus H1:Assuming that the amounts spent by female and male charge customers at Q-Mart are normally distributed, based on the procedure advocated by Bluman, what is/are the critical values that you would use to conduct this test of hypothesis? Place your answer, rounded to 3 decimal places, in the blank. If there are two critical values, place only the positive value in the blank. For example, 2.035 would be a legitimate entry. ____________Question 14 of 17 3.0 PointsAccepted 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? = 0.05. Version A Version BSample size 45 65Mean score 8.8 8.2Sample variance 2.6 2.4What is the test value for this hypothesis test?Answer: _________ 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: _____________ 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: ___________ Enter only a 1 or 2 for your answer. Question 15 of 17 1.0 PointsIn conducting hypothesis testing for difference between two means when samples are dependent (paired samples), the variable under consideration is, the sample mean difference between the pairs. True FalseQuestion 16 of 17 1.0 PointsIn a simple linear regression problem, the least squares line is y' = -3.2 + 1.3X, and the coefficient of determination is 0.7225. The coefficient of correlation must be ?0.85. True FalseQuestion 17 of 17 1.0 PointsIf there is no linear relationship between two variables X and Y, the coefficient of determination, R2, must be 1.0. True False

 

Paper#61679 | Written in 18-Jul-2015

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