MATH302 QUIZ 5

ProfArgeol

quiz_5_math302.pdf

Home >Mathematics homework help >MATH302 QUIZ 5

Sites MATH302 K004 Fall 13 Tests & Quizzes ?Log Out

Quiz 5 MATH302

Part 1 of 8 -

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.t - distributed with 98 degrees of freedom

C.chi-squared distributed with 99 degrees of freedom

D.normally distributed

Reset Selection

Question 3 of 17 1.0 Points

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

Perform an appropriate test of hypothesis to determine if there is evidence, at the .05 level of significance, to support the claim that the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant? What is the value of the sample test statistic?

A.z = 1.8424 B.t = 2.7234 C.t = 1.8424 D.p = 2.7234

Reset Selection

Part 2 of 8 -

Question 4 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 negative. C.As x increases, y decreases, and the correlation coefficient must be positive. D.As x increases, y increases, and the correlation coefficient must be negative.

Reset Selection

Question 5 of 17 1.0 Points

____________ is/are especially helpful in identifying outliers. A.Linear regression B.Regression analysis C.Scatterplots D.Normal curves

Reset Selection

Question 6 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: A.20% B.25%

C.80% D.50%

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.20% B.50% C.80% D.25%

Reset Selection

Question 8 of 17 1.0 Points

A correlation value of zero indicates. A.a strong linear relationship B.a perfect linear relationship C.no linear relationship D.a weak linear relationship

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 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.

Part 4 of 8 -

Question 10 of 17 1.0 Points

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.

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.

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.

Apartments.xlsx

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.

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:

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

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.

Part 6 of 8 -

Question 14 of 17 3.0 Points

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?

Answer: 0.39 Round your answer to two decimal places.

What is the P-value for this hypothesis test?

Answer: 0.357 Round your answer to three decimal places.

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.

Answer: 2 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

When the actual values y of a response variable and the corresponding predicted values y' are the same, the standard error of the estimate will be zero.

True False

Reset Selection

Question 17 of 17 1.0 Points

In 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 False

Reset Selection

Save

Exit

Switch to Full View