Stats Help

Chapter 3

In a particular university, a graduate program in management requires GRE quantitative scores of 550 or better. This year’s entering class has n=20 and M=630. Is it characteristic of a national population of graduate students for whom =520 with = 100? What’s the probability that a group of applicants selected at random would have M= 525 or better?

Members of a sales staff complete a survey that measures their levels of optimism

and score as follows: 12,15,16,17,21,24,24,26,28,31. If the population standard

deviation is 4.0:

a. What’s the value of the standard error of the mean?

b. What’s the z value for a z-test with this group if = 25.0?

c. If 26.0 is the mean for all employed adults, is this group of sales personnel

significantly different?

Chapter 4

An advertising agency is commissioned to develop a store display advertising a

new detergent. To gauge the effectiveness of the display, the number of detergent

boxes sold in six stores where the display was placed (Group 1) is compared to

the number of detergent boxes sold in six similar stores where the display was not

present (Group 2). The data are as follows:

Group 1: 10,15,17,12,12,14

Group 2: 10, 12, 12, 11, 13, 9.

a. Is the difference significant?

b. Write out the null and the alternate hypotheses for this problem.

c. What is Cohen’s value, and what does it indicate in this case?

d. Was the store display effective in boosting the sales of the new detergent?

Chapter 5-

A courier service is comparing the number of parcels delivered on each of 5 work-

days in a major city one, two, and three weeks after opening its doors.

· 1 week: 4, 6, 13, 15, 19

· 2 week: 11, 16, 17, 20, 21

· 3 week: 2, 7, 9, 10, 10

a. Is F significant?

b. Which week(s) is/are different from which?

c. What does the effect size indicate??

The manager of an agency providing temporary employees to city offices is analyzing the number of days temporary hires typically work in different types of

positions. The data are as follows:

Answer question # 10a, 10b, and 10c (page 133) using the following data:

· Legal clerical: 3, 2, 4, 4, 2, 6, 4

· Accounting: 5, 4, 7, 9, 9, 7, 8

· Insurance: 2, 3, 4, 5, 6, 7, 8

Are there significant differences in the length of time temps work in the different industries?

b. How much of the difference can be explained by the industry?

c. Which groups are significantly different from which?

Chapter 6

The CEO at a sheet metal manufacturing plant is analyzing the company’s day versus

night shift production during a two-week period before and after workers received a

raise. Data are as follows: cells a and b represent level 1 of main effect 1 and:

Day workers before the raise (in tons): 7.5, 7.7, 7.7, 8.9, 8.2

Day workers after the raise: 7.9, 8.5, 8.8, 8.9, 9.0

Night workers before the raise: 6.6, 6.3, 6.9, 7.1, 7.0

Night workers after the raise: 6.5, 6.1, 6.0, 6.0, 5.9

a. How much of the variability is explained by shift?

b. Why is no post hoc test necessary in problems of this type?

c. if there is variability in sheet metal production related to the weather,

where will it emerge?

d. How should a partial eta for between be interpreted?

Chapter 7

Answer question # 3a, 3b, 3c, and 3d (page 190) using the following data:

Eight participants attend three consecutive sessions in a business seminar. In the

first there is no reinforcement for responding to the session moderator’s questions.

In the second, those who respond are provided with positive feedback as reinforcement. In the third, responders receive cafeteria discount coupons. The number of times the participants responded in each session is provided below.

	None	Feedback	Coupons
1.	1	3	4
2.	2	4	5
3.	3	4	5
4.	4	6	7
5.	2	4	5
6.	5	6	8
7.	2	3	3
8.	2	3	8

a. Did the different reinforcers have significantly different effects on the number of responses? If so, which reinforcers are significantly different from

which? Rank the reinforcers from most to least effective.

b. Calculate and explain the effect size.

c. If instead of having the same participants attend the three sessions, three

different groups of participants attended one session each, and the table

above showed the number of responses in each of those groups, how would

your answers to the above two questions have changed? Perform all your

calculations again.

d. Why are the F values of the two answers different?

Answer question #4a, 4b, 4c, and 4d (page 191) using the data given in the problem

Eight college students take summer jobs as door-to-door sales representatives for

a cleaning supplies company. Their number of sales made per week during their

first four weeks of summer employment are as follows.

	Week 1	Week 2	Week 3	Week 4
1.	4	6	7	9
2.	5	6	6	8
3.	3	4	5	7
4.	2	4	8	10
5.	4	6	8	9
6.	3	4	6	9
7.	5	5	5	7
8.	4	4	6	6

a. Are there significant differences among the weeks?

b. Which weeks are significantly different from which?

c. Is sales success related to experience?

d. How much of the variations in sales can be explained by amount of experience?

Chapter 8

Answer the two questions in # 3 (page 217) using the data in the problem. Ensure that you show all relevant work.

Ten employees have just taken two surveys on a) their job satisfaction and b) their

life satisfaction. For both variables, higher scores indicate more satisfaction. The

data are ordinal. Is the relationship random?

	Job	Life
1.	15	10
2.	5	4
3.	16	11
4.	10	8
5.	11	13
6.	3	4
7.	12	10
8.	11	8
9.	10	7
10.	14	9