Test 1 - Pulled from Dr. Lai\'s test bank, assortment of questions with answers underneath. PDF

Preview

Summary

Pulled from Dr. Lai's test bank, assortment of questions with answers underneath....

Description

QMET352-002-202020 Advanced Business Statistics Started on Wednesday, 11 September 2019, 8:49 PM State

Finished

Completed on Wednesday, 11 September 2019, 9:24 PM Time taken 34 mins 49 secs

Question 1 Correct Marked out of 1

An investigation of the effectiveness of a training program to improve customer relationships included a pre-training and post-training customer survey. Seven customers were randomly selected and completed both surveys. The results follow. Customer Pre-training survey Post-training survey A 6 8 B 5 5 C 10 10 D 7 10 E 6 8 F 5 6 G 2 8 This analysis is an example of Select one:

a. Paired t-test. b. Two sample t test of means. c. Two sample z test of means. d. Z test of proportions

The correct answer is: Paired t-test.

Question 2 Incorrect Marked out of 1

For a hypothesis comparing two population means, what is the critical value for a one-tailed hypothesis test, using a 5% level of significance level, with both sample sizes equal to 13? The standard deviations for the samples are 5 and 7. Assume the population standard deviations are unequal. Select one:

a. 1.717 b. 1.721 c. 1.711 d. 2.074 e. 2.064

Assumptions: population standard deviations unknown and unequal => t-Test. We need to use formula [11-6] on page 361 to calculate df. 2 s12 = 52 = 25 s22 = 7 = 49 n1 = 13 n2 = 13 df = [(25/13 + 49/13)^2] / [((25/13)^2)/12 + ((49/13)^2)/12] = 21.72 = 21 (the usual practice is to round down) a = 0.05, one-tailed test, df = 21 => t critical value = 1.721 The correct answer is: 1.721

Question 3 Incorrect Marked out of 1

A company is researching the effectiveness of a new website design to decrease the time to access a website. Five website users were randomly selected, and their times (in seconds) to access the website with the old and new designs were recorded. To compare the times, they computed (new website design time - old website design time). The results follow. User Old Website Design New Website Design A B

30 45

25 30

C D

25 32

20 30

E

28

27

What is the alternate hypothesis?

Select one:

a. H1: µd = 0 b. H1: µd < 0 c. H 1: µ d ≠ 0 d. H1: µd > 0

Your answer is incorrect.

This is a one-tailed test because the purpose of the new design is to decrease access times. So calculating the difference (new design time - old design time), we expect this difference to be less than zero. The alternate hypothesis would be H1: µd < 0, and the null hypothesis would be H0 : µd ≥ 0. The correct answer is: H1: µd < 0

Question 4 Incorrect Marked out of 1

The information of the mean dollar sales per retail outlet of two products is summarized below. The sales amount are assumed to be approximately normally distributed for both products. Assume that the population standard deviations are equal. At the .01 significance level, does Product 1 has a higher mean dollar sales record than Product 2? Question to address here: what is the test statistic for this hypothesis test? Product 1

Sample Size Sample Mean Sample Standard Deviation 15 $3425 200 16

Product 2

$3250

175

Select one:

a. p-statistic b. z-statistic c. t-statistic d. df-statistic

Your answer is incorrect. Population standard deviations unknown but equal, thus t test is called for. The correct answer is: t-statistic

Question 5 Incorrect Marked out of 1

Accounting procedures allow a business to evaluate their inventory costs based on two methods: LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in $000s) for five products with the LIFO and FIFO methods. To analyze the difference, they computed (FIFO - LIFO) for each product. Based on the following results, does the LIFO method result in a lower cost of inventory than the FIFO method? Product FIFO (F) LIFO (L) 1

225

221

2

119

100

3

100

113

4

212

200

5

248

245

This example is what type of test? Select one:

a. A one-sample test of means b. A z test for the mean c. A paired t-test d. A two-sample test of means e. A test of proportions

This is a paired t-test. We obtain information on each product using both the LIFO and FIFO methods and compute the difference in costs for each product. The null hypothesis is that the mean differences will be less than or equal to zero. The correct answer is: A paired t-test

Question 6 Correct Marked out of 1

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 related to the samples are presented below. Process A

Process B

Mean

0.002 mm

0.0026 mm

Standard deviation

0.0001 mm

0.00012 mm

Sample size

12

14

The researcher is interested in determining whether there is evidence that the two processes yield different average errors. Assume that the population standard deviations are equal. What is the null hypothesis? Select one:

a. H0: µA = µB b. H0: µA not equal to µB c. H0: µA µB

The correct answer is: H0: µA = µB

Question 7 Correct

A recent study focused on the amount of money single men and women save monthly. The information is summarized next.

Marked out of 1

Sample Size Sample Mean Population Standard Deviation 25 23 5

Men Women

30

28

10

At the .01 significance level, can we claim that women save more money than men? What is the value of the test statistic for this hypothesis test? Select one:

a. 2.632 b. 6.213 c. 6.85 d. 2.40 e. 1.318

Your answer is correct. We know population standard deviations, thus two-sample z test of means is called for. 2

2

z = (28 - 23)/sqrt(10 /30 + 5 /25) = 2.40 The correct answer is: 2.40

Question 8 Correct

A recent study focused on the amount of money single men and women save monthly. The information is summarized next.

Marked out of 1

Sample Size Sample Mean Population Standard Deviation Men Women

25 30

23 28

5 10

At the .02 significance level, can we claim that there is a difference in the saving between women and men? What is the decision rule for this hypothesis? Select one:

a. reject Ho if Z > 2.33 b. reject Ho if Z > 2.33 or Z < -2.33 c. reject Ho if Z < -2.05 or Z > 2.05 d. reject Ho if Z < -2.58 or Z > 2.58 e. reject Ho if Z < -2.33

Your answer is correct. We know both population standard deviations, thus z test is needed. Ho: Uwomen = Umen H1: Uwomen ≠ Umen The claim is that "there is a difference in the saving between women and men". The keyword "difference" indicates that we are dealing with a two-tailed z test. Thus 0.5 - a/2 = 0.5 - 0.02/2 = 0.4900 the area. The closet area on z table to be found is 0.4901, which corresponds to z = 2.33. Decision rule: reject Ho if Z > 2.33 or Z < -2.33 The correct answer is: reject Ho if Z > 2.33 or Z < -2.33

Question 9 Incorrect Marked out of 1

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 related to the samples are presented below. Process A

Process B

Mean

0.002 mm

0.0026 mm

Standard deviation

0.0001 mm

0.00012 mm

Sample size

12

14

The researcher is interested in determining whether there is evidence that the two processes yield different average errors. Assume that the population standard deviations are equal. If we test the null hypothesis at the 1% level of significance, what is the decision rule of the test? Select one:

a. Decision rule: reject Ho if t > 2.797 or t < -2.797 b. Decision rule: reject Ho if t > 2.779 or t < -2.779 c. Decision rule: reject Ho if t > 2.492 or t < -2.492 d. Decision rule: reject Ho if t > 2.787 or t < -2.787 e. Decision rule: reject Ho if t > 2.485 or t < -2.485

Ho: UA = UB H1: UA ≠ UB Decision rule: reject Ho if t > 2.797 or t < -2.797 (with the assumption that the population standard deviations are equal, thus df = 12+14-2 = 24, a = 0.01, two-tailed test because the claim keyword "different average errors")

The correct answer is: Decision rule: reject Ho if t > 2.797 or t < -2.797

Question 10 Correct Marked out of 1

Accounting procedures allow a business to evaluate their inventory costs based on two methods: LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in $000s) for five products with the LIFO and FIFO methods. To analyze the difference, they computed (FIFO - LIFO) for each product. Based on the following results, does the LIFO method result in a lower cost of inventory than the FIFO method? Product FIFO (F) LIFO (L) 1

225

221

2

119

100

3

100

113

4

212

200

5

248

245

What is the value of calculated t? Select one:

a. -2.028 b. ±2.776 c. 0.933 d. +0.470

This is a one-tailed test because we think that the LIFO method will compute lower inventory costs than the FIFO method. So calculating the difference (FIFO - LIFO), we expect this difference to be greater than zero. The t-statistic is applied. To find the value of the test statistic, calculate the mean and standard deviation of the differences for the five products. First calculate the difference (FIFO - LIFO): 225 - 221 = 4 119 - 100 = 19 100 - 113 = -13 212 - 200 = 12 248-245 = 3 mean difference d bar = (4 + 19 - 13 + 12 + 3)/5 = 25/5 = 5 2

2

2

2

standard deviation of the difference sd = sqrt{[(4-5) + (19-5) + (-13-5) + (12-5) + (32 5) ]/(5-1)} = sqrt(574/4) = 11.979 t = 5/[11.979/sqrt(5)] = 0.933 The correct answer is: 0.933

Return to: Module 2 

https://moodle.louisiana.edu/mod/quiz/review.php?attempt=1387103

8/8...