Assignment:
Q1: A random sample of 15 observations from the first population revealed a sample mean of 350 and a sample standard deviation of 12. A random sample of 17 observations from the second population revealed a sample mean of 342 and a sample standard deviation of 15. At the .10 significance level, is there a difference in the population means?
Q2: Ms. Lisa Monnin is the budget director for Nexus Media, Inc. She would like to compare the daily travel expenses for the sales staff and the audit staff. She collected the following sample information.
|
Sales ($)
|
131
|
135
|
146
|
165
|
136
|
142
|
|
|
Audit ($)
|
130
|
102
|
129
|
143
|
149
|
120
|
139
|
At the .10 significance level, can she conclude that the mean daily expenses are greater for the sales staff than the audit staff? What is the p-value?
Q3: The management of Discount Furniture, a chain of discount furniture stores in the Northeast, designed an incentive plan for salespeople. To evaluate this innovative plan, 12 salespeople were selected at random, and their weekly incomes before and after the plan were recorded.
|
Salesperson
|
Before
|
After
|
|
Sid Mahone
|
$320
|
$340
|
|
Carol Quick
|
290
|
285
|
|
Tom Jackson
|
421
|
475
|
|
Andy Jones
|
510
|
510
|
|
Jean Sloan
|
210
|
210
|
|
Jack Walker
|
402
|
500
|
|
Peg Mancuso
|
625
|
631
|
|
Anita Loma
|
560
|
560
|
|
John Cuso
|
360
|
365
|
|
Carl Utz
|
431
|
431
|
|
A. S. Kushner
|
506
|
525
|
|
Fern Lawton
|
505
|
619
|
Was there a significant increase in the typical salesperson's weekly income due to the innovative incentive plan? Use the .05 significance level. Estimate the p-value, and interpret it.
Q4: Fairfield Homes is developing two parcels near Pigeon Fork, Tennessee. In order to test different advertising approaches, they use different media to reach potential buyers. The mean annual family income for 75 people making inquiries at the first development is $150,000, with a standard deviation of $40,000. A corresponding sample of 120 people at the second development had a mean of $180,000, with a standard deviation of $30,000. At the .05 significance level, can Fairfield conclude that the population means are different?