Question

Ten soldiers were selected at random from each of two companies to participate in a rifle shooting competition. Summary information for the shooting scores is given in the following table:
Scores

Company n Mean Std. Dev.

Dog 10 56.80 14.61

Fox 10 62.20 13.99
(a) Give a 95% confidence interval for the difference in shooting scores between Dog and Fox company.
(b) Based on this confidence interval, can we conclude that there is a difference in the shooting accuracy between Dog and Fox company? Why or why not?

Answer 1

(a)

= 0.05

ndf = n1 + n2 - 2 =10 + 10 - 2 = 18

From Table, critical values of t 2.1009

Confidence interval:

(56.80 - 62.20) (2.1009 X 6.3967)

= - 5.4 13.4388

= (-18.8388 , 8.0388)

So,

Confidence Interval:

- 18.8388 < < 8.0388

(b)

Based on this confidence interval, we cannot conclude that there is a difference in the shooting accuracy between Dog and Fox company because 0 is included in the confidence interval.