Question

b) Medical research has shown that repeated wrist extension beyond 18 degrees increases the risk of wrist and hand injures. 40 students atschool used a proposed new mouse design, and while using the mouse their wrist extensions were recorded for each one. The mean wrist extension for theses 40 students was 20 with a sample standard deviation of 3. i. (2 points) To test the hypothesis that the mean wrist extension for people using this new mouse design exceeds 18 degrees, which test should be used? A. Z-test B. T-test ii. (2 points) Which of the following is the alternative hypothesis? A. Ha : µ = 18 B. Ha : µ < 18 C. Ha : µ > 18 D. Ha : µ 6= 18

Answer 1

Solution :

Given that

= 18

=20

S =3

n = 40

This is the tright tailed test .

The null and alternative hypothesis is ,

H0 :    = 18

Ha : > 18

Test statistic = t

= ( - ) / S / n

= (20 - 18) / 3 / 40

= 4.216

Test statistic = t = 4.216