Question

A lathe is set to cut bars of steel into lengths of 6 centimeters. The lathe is considered to be in perfect adjustment if the average length of the bars it cuts is 6 centimeters. A sample of 121 bars is selected randomly and measured. It is determined that the average length of the bars in the sample is 6.08 centimeters. The population standard deviation is 0.44 centimeters. The correct null hypothesis for this problem is the average length is less than 6.0 centimeters the average length is less than or equal to 6.0 centimeters the average length equals 6.0 centimeters the average length is greater than or equal to 6.0 centimeters

Answer 1

The answer is "6 cm".

Explanation:

In this question, the third choice is correct because the average length is equal to the 6.0 cm in the testing of the bars that is equal to 6 cm.

In other words, we can say that by using the z statistic formula that is
`Z=(x-\mu)/(\sigma)` its average length value is equal to 6 cm.