# Minitab Notes for Activity 6

## Entering the Data (Question 4)

- Label an empty column of the worksheet as "mass"
- Enter the masses that you collected in question 4 in that column.

## Summarize the Sample (Question 5)

- Choose Stat / Basic Statistics / Display Descriptive Statistics
- Select the mass variable
- Click OK.

## Finding the Critical Values (Question 12)

The easiest way to find the critical values is to go to Table T in your
appendix and look up the value(s).

However, if you want to do this with Minitab, you can do the following.
These instructions assume you're using a t distribution. If you're using a
normal distribution, then choose normal in step 1 instead of t and ignore
the part about degrees of freedom.

- Choose Calc / Probability Distributions / t
- Check Inverse Cumulative Probability
- Enter the proper degrees of freedom
- Click the Input Constant radio button
- Enter the area to the left of the critical value into the Input Constant
box. Minitab always takes the area to the left, so you'll have to adjust if
you're not working with a left tail already.
- If you have a left tail test, this is α. For example, if your
significance level was 0.10, then you would enter 0.10 into the box.
- If you have a right tail test, this is 1-α. For example, if your
significance level was 0.10, then you would enter 0.90 into the box.
- If you have a two tail test, then you need to repeat this whole process
two times. The first time, use α/2 for the area on the left and
1-α/2 for the area on the right. For example, if your significance
level was 0.10, then there would be half of that (0.05) on each side. The
first time through, you would use 0.05 and the second time through you would
use 0.95.

- Click OK

## Finding the Test Statistic, P-value, and Confidence Interval (Questions
13-15)

- Go to Stat / Basic Statistics / 1-Sample t
- Select mass as your variable to test
- Enter the claimed mean in the "test mean" box
- Go into options
- The confidence interval should agree with your significance level. If
your significance level is 0.10 (10%), then your confidence level should be
90%.
- Make sure the alternative hypothesis is set properly for your
problem.
- Click OK

- Click OK

Notice how the summary statistics are given. You didn't have to do a
separate step in question 5 to find them, they're given here. However, we
wanted to check for normality, so it was a good thing we did question 5.

## Changing to a One-Tail Test (Question 23)

- Repeat the section above, but under options, change the alternative to
be a greater than.
- Click OK