Introduction to Probability and Statistics for Engineers and Scientists

538 Chapter 12:Nonparametric Hypothesis Tests

Use these data to test the hypothesis that the median salary of physicians in 1990

was not greater than in 1987. What is thep-value?

6. An experiment was initiated to study the effect of a newly developed gasoline
   detergent on automobile mileage. The following data, representing mileage per
   gallon before and after the detergent was added for each of eight cars, resulted.

Mileage Mileage

Car without Additive with Additive

1 24.2 23.5

2 30.4 29.6

3 32.7 32.3

4 19.8 17.6

5 25.0 25.3

6 24.9 25.4

7 22.2 20.6

8 21.5 20.7

Find thep-value of the test of the hypothesis that mileage is not affected by the

additive when

(a) the sign test is used;

(b) the signed rank test is used.

7. Determine thep-value when using the signed rank statistic in Problems 1 and 2.


8. Twelve patients having high albumin content in their blood were treated with
   a medicine. Their blood content of albumin was measured before and after
   treatment. The measured values are shown in the table.

Blood Content of Albumina

Patient N Before Treatment After Treatment

1 5.02 4.66

2 5.08 5.15

3 4.75 4.30

4 5.25 5.07

5 4.80 5.38

6 5.77 5.10

7 4.85 4.80

8 5.09 4.91

9 6.05 5.22

(continued)