RES342 – Quiz 2
Name: ______
Multiple Choice –Circle the one best answer.
1. A poll of 400 people from Dobbs Ferry showed 250 preferred chocolate raspberry coffees while 170 out of 350 in Irvington preferred the same flavor. To test the hypothesis that there is no difference in preferences in the two villages, what is the alternate hypothesis?
A)
B)
C)
D)
2. Suppose we are testing the difference between two proportions at the 0.05 level of significance. If the computed z is –1.07, what is our decision?
A) Reject the null hypothesis
B) Do not reject the null hypothesis
C) Take a larger sample
D) Reserve judgment
3. When is it appropriate to use the paired difference t-test?
A) Four samples are compared at once
B) Any two samples are compared
C) Two independent samples are compared
D) Two dependent samples are compared
4. Using two independent samples, two population means are compared to determine if a difference exists. The number in the first sample is fifteen and the number in the second sample is twelve. How many degrees of freedom are associated with the critical value?
A) 24
B) 25 Note that this really depends on whether we can pool the variances or not.
C) 26
D) 27
Printed: 10/4/2018 1 RES342-r5-quiz2-June2009-student
. updated 21 June 2009
RES342 – Quiz 2
Use the following information to answer questions 5 – 10.:
A national manufacturer of ball bearings is experimenting with two different processes for producing precision ball bearings. It is important that the diameters be as close as possible to an industry standard. The output from each process is sampled and the average error from the industry standard is calculated. The results are presented below.
Process A / Process BMean / 0.002mm / 0.0026mm
Standard Deviation / 0.0001mm / 0.00012mm
Sample Size / 12 / 14
The researcher is interested in determining whether there is evidence that the two processes yield different average errors.
5. What is the null hypothesis?
A)
B)
C)
D)
6. What is the alternate hypothesis?
A)
B)
C)
D)
7. What is the degrees of freedom?
A) 10
B) 13
C) 26
D) 24
8. What is the critical t value at the 1% level of significance?
A) +2.779
B) –2.492
C) 1.711
D) 2.797
9. Assume calculated t to be +2.70, at the 0.01 level of significance what would be the decision?
A) Reject the null hypothesis and conclude the means are different.
B) Reject the null hypothesis and conclude the means are the same.
C) Fail to reject the null hypothesis and conclude the means are the same.
D) Fail to reject the null hypothesis and conclude the means are different.
10. This example is what type of test?
A) One sample test of means.
B) Two sample test of means.
C) Paired t-test.
D) Test of proportions.
Use the following information to answer questions 11-16:
Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in $ thousands) for five products both ways. Based on the following results, is LIFO more effective in keeping the value of his inventory lower?
Product
/ FIFO (F) / LIFO (L) / Difference (D)1 / 225 / 221 / 4
2 / 119 / 100 / 19
3 / 100 / 113 / -13
4 / 212 / 200 / 12
5 / 248 / 245 / 3
df = 4
11. What is the null hypothesis if we are to create a right tailed test ?
A)
B)
C)
D)
12. What is the alternate hypothesis?
A)
B)
C)
D)
13. What are the degrees of freedom?
A) 4
B) 5
C) 15
D) 10
E) 9
14. If you use the 5% level of significance, what is the critical t value?
A) +2.132
B) - 2.776
C) + 2.262
D) - 2.228
15. What is the value of calculated t?
A) +0.93
B) - 2.776
C) +2.47
D) –2.028
16. What is the decision at the 5% level of significance?
A) Fail to reject the null hypothesis and conclude LIFO is more effective.
B) Reject the null hypothesis and conclude LIFO is more effective.
C) Reject the alternate hypothesis and conclude LIFO is more effective.
D) Fail to reject the null hypothesis and conclude LIFO is not more effective.
Printed: 10/4/2018 1 RES342-r5-quiz2-June2009-student
. updated 21 June 2009