Question

The accuracy of a coin counter machine is guaged to accept nickelswith a mean diameter of 21.21mm. A sample of 37 nickels was drawn from a reported defective coin counter machine located near a school. The sample had a sample mean of 21.21 mm and a sample SD 0.011 mm.

Test the claim that the mean nickel diameter accepted by this coin counter machine is greater than 21.21 mm. Test at the 0.05 significance level.

A. Identify the correct alternative hypothesis Ha. = OR > OR < 21.21?

B. the test statistic value is ______?

C. Using the traditional method, the critical value is ______?

D. Do you reject Ho OR fail to reject Ho?

Answer 1

A. Here the claim is that the mean nickel diameter accepted by this coin counter machine is greater than 21.21 mm.

So hypothesis is vs

B. Test statistics t is to be used, as population standard deviation is not known

C. The t-critical value for a right-tailed test, for a significance level of α=0.05 is

tc​=1.688

Graphically

D. As t statistics do not fall in the rejection region, we fail to reject the null hypothesis (H0)