Question

QUESTION 3

1. During the Middle Ages, armies often used catapults to launch flaming projectiles at their enemies. Because of the inferior materials and manufacturing processes of the time, excessive variability in the weight of flaming projectiles could damage the arm of a catapult, thus leading to inaccurate launches. Because of this problem, most armies maintained a staff of quality engineers to inspect projectiles prior to their use. During the Hundred Years’ War, the English army applied the following hypothesis test to each shipment of projectiles they received.

   They used a level of significance of 0.05 and a sample of size 25. Suppose for one particular shipment the test statistics was 30.

   You fail to reject null hypothesis.

   True

   False

Answer 1

Here alternative hypothesis is two tailed.

H_a : Average Weight of projectile is not different than $\mu_0$ .

Hence for z test, at 5% level of significance, critical value = $\pm$ 1.96.

Since calculated value of test statistic is greater than 1.96, we reject null hypothesis.

Hence given statement is false.