# 8.2.2.2 - Minitab Express: Confidence Interval of a Mean

Here you will learn how to use Minitab Express to construct a confidence interval for a mean. The procedure is similar to the one that you learned earlier in this lesson for constructing a confidence interval for a proportion. The following example walks through this procedure when data are in a Minitab Express work. At the bottom of this page you will find instructions for using Minitab Express with summarized data.

## MinitabExpress – Confidence Interval for a Mean

To create a 95% confidence interval of mean height in Minitab Express:

1. Open the data set:
2. On a PC: In the menu bar select STATISTICS > One Sample > t
3. On a Mac: In the menu bar select Statistics > 1-Sample Inference > t
4. In this case we have our data in the Minitab Express worksheet so we will use the default Sample data in a column
5. Double click the variable Height in the box on the left to insert the variable into the Sample box
6. Click on the Options tab
7. The default Confidence level is 95
8. Click OK

This should result in the following output:

Descriptive Statistics
N Mean StDev SE Mean 95% CI for $$\mu$$
525 67.0090 4.4616 0.1947 (66.6265, 67.3916)

$$\mu$$: mean of Height

Video Walkthrough

Select your operating system below to see a step-by-step guide for this example.

## What if we have summarized data and not data in a Minitab Express worksheet? Section

If you do not have a Minitab Express worksheet filled with data concerning individuals, but instead have summarized data (e.g., the values of $$s$$, $$\overline{x}$$, and $$n$$), you would skip step 1 above and in step 3 you would select Summarized data