220.127.116.11.1 - Minitab Express: 1 Sample Mean t Test, Raw Data
MinitabExpress – One Sample Mean t Test Using Raw Data
Research question: Is the mean GPA in the population different from 3.0?
Null hypothesis: \(\mu\) = 3.0
Alternative hypothesis: \(\mu\) ≠ 3.0
The GPAs of 226 students are available.
A one sample mean \(t\) test should be performed because the shape of the population is unknown, however the sample size is large (\(n\) ≥ 30).
To perform a one sample mean \(t\) test in Minitab Express using raw data:
- Open Minitab data set:
- On a PC: Select STATISTICS > One Sample > t
On a Mac: Select Statistics > 1-Sample Inference > t
- Double-click on the variable GPA to insert it into the Sample box
- Check the box Perform a hypothesis test
- For the Hypothesized mean enter 3
- Click the Options tab
- Use the default Alternative hypothesis of Mean ≠ hypothesized value
- Use the default Confidence level of 95
- Click OK
This should result in the following output:
|N||Mean||StDev||SE Mean||95% CI for \(\mu\)|
\(\mu\): mean of GPA
|Null hypothesis||H0: \(\mu\) = 3|
|Alternative hypothesis||H1: \(\mu\) ≠ 3|
Select your operating system below to see a step-by-step guide for this example.
We could summarize these results using the five step hypothesis testing procedure:
We do not know if the population is normally distributed, however the sample size is large (\(n \ge 30\)) so we can perform a one sample mean t test.
\(H_0: \mu = 3.0\)
\(H_a: \mu \ne 3.0\)
\(t (225) = 6.81\)
\(p < 0.0001\)
\(p \le \alpha\), reject the null hypothesis
There is evidence that the mean GPA in the population is different from 3.0