8.2.2.2 - Minitab: Confidence Interval of a Mean

Here you will learn how to use Minitab 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 work. At the bottom of this page you will find instructions for using Minitab with summarized data.

Minitab 18

Minitab®  – Confidence Interval for a Mean

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

  1. Open the data set: fall2016stdata.mpx
  2. In Minitab, select Stat > Basic Statistics > 1-sample t
  3. In this case we have our data in the Minitab worksheet so we will use the default One or more samples, each in a column
  4. Double click the variable Height in the box on the left to insert the variable into the box
  5. Select Options
  6. The default Confidence level is 95
  7. Click OK and OK

This should result in the following output:

Descriptive Statistics

N Mean StDev SE Mean 95% CI for \(\mu\)
525 67.009 4.462 0.195 (66.627, 67.392)

\(\mu\): mean of Height

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

If you do not have a Minitab 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