CHAPTER 11 Two-Sample Tests of Hypothesis SOLVED PROBLEMS

Problem 11-3

Problem 11-3 (Cont.) p- value = = >  p - value= Z

Problem 11-4

Problem 11-4 (Cont.) Z

Problem 11-5

Problem 11-5 (Cont.) =.0039 p-value =.0039 x 2 =.0078,.0078<.01; Z

Problem 11-6

Problem 11-8

Problem 11-11

Problem 11-12

Problem 11-14

Problem 11-14(contd.)

Problem 11-15

Problem 11-15(contd.)

Problem 11-16

Problem 11-16(contd.)

Problem 11-19

Problem cont’d..

Problem 11-25(a) Find the 95% CI for when x=20

Problem (b)

Problem 11-28

Problem contd. DR: FTR H o when p-value >  P-value = = >.05 p-value >  Therefore, FTR H o.

Problem 11-32

Problem (Cont.) z

Problem 11-33

Problem contd.. DR: FTR H 0 if p-value > p-value.1539 >.05. There fore FTR H 0.

Problem (Cont.) z Accept Reject.025

Additional Problem (AP # 1) The air force trains enlisted computer personnel at two bases—Cass AFB and Kingston AFB. A common final examination is administered. As part of an ongoing study of the training program, a comparison of the final test scores is to be made. Is there any significant difference in the final results of the two educational programs? Use the.04 significance level. Determine the p-value. Explain your decision to the committee studying the program. Class AFB Kingston AFB Number sampled Mean score Sample standard deviation

Answer AP # 1

Answer AP #1(cont.) z

Additional problem (AP#2) Corrigan industries has been awarded a large contract to supply pipeline parts to Angus Oil, a company drilling in the Scotland-Ireland area. In the past, two subcontractors specializing in steel products have provided Corrigan industries with high quality supplies such as nuts, bolts, steel bars and casing. One of the concerns of Corrigan is the delivery time of the two subcontractors, Jackson steel and Alabama Distributors. The question to be explored is whether there is a difference in the delivery time of the two subcontractors. Random samples from the files of Corrigan Industries revealed these statistics about delivery time: Jackson Steel Alabama Distributors Number in Sample Mean Delivery time (days) Sample standard deviation (days) 4 3

Answer AP# 2

Answer AP# 2(contd.) p- value = 2( ) =