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:
- Open the file: cafedata.mpx
- In Minitab, select Stat > Basic Statistics > 1-sample t
- In this case the data is in a worksheet so select use One or more samples, each in a column
- Select the variable Coffees
- Select Options
- The default Confidence level is 95
- Click OK and OK
This should result in the following output:
| 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.