A company employs two shifts of workers. Each shift produces a type of gasket where the thickness is the critical dimension. The average thickness and the standard deviation of thickness for shift 1, based on a random sample of 37 gaskets, are 10.36 mm and 0.14 mm. The similar figures for shift 2, based on a random sample of 28 gaskets, are 10.38 mm and 0.17 mm. Let12be the mean difference in thickness between shifts 1 and 2.

A. Calculate a 95% confidence interval for12. Round your answers to three decimal places, if necessary.

1a). Lower limit:

1)b: Upper limit

2)Based on your answer to partA, are you convinced that the gaskets from shift 2 are, on average, wider than those from shift 1?

Select the following

1. Definitely.
2. Most likely.
3. Probably, not.
4. Definitely, not.

Explain. select the bold responses

B) Because the confidence interval extends from aSelect

positive/negative value to a positive/ negative value, the population mean difference could be positive/negative.

select which bold response fits best

C) How would your answers to partsaandbchange if the sample sizes were instead 370 and 280?

We aredefinitely/ most likely/ probably not/ or definitely not convinced that the gaskets from shift 2 are, on average, wider than those from shift 1.