To use JMP, click "New Data Table", then enter the data into Column 1. Double-click Column 1 and name it Fill Pressure. Now select "Analyze", "Distribution" and highlight Fill Pressure and click "Y, Columns", then
click OK. You are now looking at a histogram and stuff.
To test the hypothesis:Click the red triangle next to Fill Pressure then select "Test Mean" from the drop-down list. Enter in the mean from your null hypothesis (30)and enter in the given standard deviation (1.2). Click "OK" and JMP gives you the
hypothesis test at the bottom of the printout. Note that you cannot enter the level of significance they have given. The level of significance is not relevant to JMP, you will use that yourself to make your decision.
Prob > |z| is the P-value for a two-tailed test.
Prob > z is the P-value for an upper-tailed test.
Prob <
z is the P-value for a lower-tailed test.
Select the appropriate P-value from this list.
To make a confidence interval:
You aren't asked to make a confidence interval in this question, but why not do so to check your answer to part (a)?
Click the red triangle next to Fill Pressure
then select "Confidence Interval" from the drop-down list. Select "Other" to get a pop-up menu. Type in the level of confidence you desire as a decimal. For example, if you want a 97% confidence interval, type in 0.97. (Here, you want a 95% confidence interval, so type 0.95, which is the default value anyway.)
Make sure you click the box saying "Use known
Sigma". Click "OK" and you will then get a pop-up menu to type in the sigma value given at the start of the problem (1.2, in this case). Click "OK" and JMP gives you the Confidence Interval at the bottom of the printout.