- Example: Coffee Sales (Data in Column)

For 48 days data concerning sales were collected from one student-run cafe. Let's construct a 95% confidence interval for the mean number of coffees sold per day.

To create a 95% confidence interval of mean number of coffees sold per day in Minitab:

  1. Open the file: cafedata.mpx
  2. In Minitab, select Stat > Basic Statistics > 1-sample t
  3. In this case the data is in a worksheet so select use One or more samples, each in a column
  4. Select the variable Coffees
  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 \(\mu\)
47 21.51 11.08 1.62 (18.26, 24.76)

\(\mu\): population mean of Coffees

We are 95% confident that the population mean number of coffees solder per day is between 18.26 and 24.76.