# Stats Exam 5

**Topics:**Bone marrow, Arithmetic mean, Statistical hypothesis testing

**Pages:**13 (1534 words)

**Published:**July 22, 2012

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. Using = .05, what is the value the test statistic?

Women

Men

Sample size

50

80

Mean effect

7

6.95

Sample variance

3

4

A. t = 3.252

B. z = 0.455

C. z = 0.081

D. z = 0.151

Answer Key: D

Question 2 of 10

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 trees

Sample size

40

70

Mean trunk diameter (cm)

45

39

Sample variance

100

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 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.

Answer Key: B

Question 3 of 10

1.0 Points

A researcher hypothesizes that the variation in the amount of money spent on business dinners is greater than the variation of the amount of money spent on lunches. The variance of nine business dinners was $6.12 and the variance of 12 business lunches was $0.87. What is the test value?

A. 3.10

B. 9.61

C. 49.50

D. 7.03

Answer Key: D

Question 4 of 10

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

Answer Key: B

Question 5 of 10

1.0 Points

Consider the following scenario in answering questions 5 through 7.

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. Use these data to answer questions 5 through 7.

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 = 1.8424

C. t = 2.7234

D. p = 2.7234

Answer Key: B

Question 6 of 10

1.0 Points

Multiple myeloma or blood plasma cancer is characterized by...

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