Complete the mcq:
Q1: 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?
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Pine trees
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Spruce trees
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Sample size
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40
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70
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Mean trunk diameter (cm)
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45
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39
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Sample variance
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100
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150
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A.The data support the claim because the test value 2.78 is greater than 1.28.
B. The data support the claim because the test value 2.78 is greater than 1.64.
C.The data do not support the claim because the test value 1.29 is less than 1.64.
D. The data do not support the claim because the test value 1.29 is greater than 1.28.
Q2: Two independent samples of sizes n1 = 50 and n2 = 50 are randomly selected from two populations to test the difference between the population means, μ1-μ2 . The sampling distribution of the sample mean difference,X1‾-X2‾ is:
A. approximately normal
B. chi-squared distributed with 99 degrees of freedom
C. t - distributed with 98 degrees of freedom
D. normally distributed
Q3: Multiple 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 7
Before 158 189 202 353 416 426 441
After 284 214 101 227 290 176 290
At the .01 level of significance, is there sufficient evidence to conclude that the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant?
A.No
B.Yes
C.Cannot Determine
Q4: In choosing the "best-fitting" line through a set of points in linear regression, we choose the one with the:
A.largest number of points on the line
B.largest sum of squared residuals
C.smallest number of outliers
D.smallest sum of squared residuals
Q5: The city of Oakdale wishes to see if there is a linear relationship between the temperature and the amount of electricity used (in kilowatts). Based on the data in the table below, is there a significant linear relationship between temperature and the amount of electricity used? These data are also available in the worksheet temperature in the Excel workbook Temperature.xlsx.
Temperature (x) 73 78 85 98 93 81 76 105
Kilowatts (y) 680 760 910 1510 1170 837 600 1800
A.No, the sample correlation coefficient is equal to 0.981, which does not provide evidence of a significant linear relationship.
B.Yes, the sample correlation coefficient is equal to 0.981, which provides evidence of a significant linear relationship.
C.Yes, the sample correlation coefficient is equal to 0.878, which provides evidence of a significant linear relationship.
D.No, the sample correlation coefficient is equal to 0.098, which does not provide evidence of a significant linear relationship.
Q6: 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. y^ = 2.63 - 0.174x
B. y^= 2.63 + 0.724x
C. y^ = 1.45 + 0.724x
D. y^= 1.45 + 0.074x
Q7: The standard error of the estimate, sest, is essentially the
A.standard deviation of the residuals
B.mean of the explanatory variable
C.standard deviation of the explanatory variable
D.mean of the residuals
Q8: Outliers are observations that
A.lie outside the sample
B.disrupt the entire linear trend
C.render the study useless
D.lie outside the typical pattern of points
Q9: 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: Round your answer to two decimal places.
At the 0.05 level of significance, what is the critical value?Q10 1.0 Points
Q10: 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
Find the equation of the regression line for these data. What is the value of the standard error of the estimate? Place your answer, rounded to 3 decimal places, in the blank. Do not use a dollar sign. For example, 0.345 would be a legitimate entry.
Q11: 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.
Q12: 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 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 test
H0: versus H1: μW=μM and μW≠μM
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.
Q13: 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.
Q14: 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 special coating is applied to several scale model engine nacelle body shapes to determine if it reduces the drag coefficient. The following data are the drag coefficient before the coating is applied and after.
Model #1 #2 #3 #4 #5 #6
Before 0.782 0.656 0.541 0.250 0.323 0.888
After 0.668 0.581 0.532 0.241 0.334 0.891
Perform a hypothesis test to determine if there is evidence at the 0.05 level of significance to support the claim that the coating reduces the drag coefficient.
What is the test value for this hypothesis test?
What is the P-value for this hypothesis test?
What is your conclusion for this test? Choose one.
1. There is sufficient evidence to show the coating reduces the drag coefficient.
2. There is not sufficient evidence to show that the coating reduces the drag coefficient.
3. There is sufficient evidence to show that the drag coefficient changed after the coating was applied.
4. There is sufficient evidence to show that the drag coefficient increased after the coating was applied.
Q15: When testing the equality of two population variances, the test statistic is the ratio of the population variances; namely .
True
False
Q16: If there is no linear relationship between two variables X and Y, the coefficient of determination, R2, must be 1.0.
True
False
Q17: A simple linear regression equation is given by y' = 5 + 3x. The predicted value of Y when X = 3 is 5.
True
False