# 8.2.2.2 - Minitab Express: Confidence Interval of a Mean

8.2.2.2 - Minitab Express: Confidence Interval of a MeanHere 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:

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

This should result in the following output:

N | Mean | StDev | SE Mean | 95% CI for \(\mu\) |
---|---|---|---|---|

525 | 67.0090 | 4.4616 | 0.1947 | (66.6265, 67.3916) |

\(\mu\): *mean of Height*

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?

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*.