1-Sample t-Test
Help > Help > Stat Menu > Basic Statistics > 1-Sample t > example
Measurements were made on nine widgets. You know that the distribution of widget measurements has
historically been close to normal, but suppose that you do not know σ. To test if the population mean is 5
and to obtain a 90% confidence interval for the mean, you use a t-procedure.
1
2
3
4
5
6
Open the worksheet Exh_stat.MTW.
Choose Stat > Basic Statistics > 1-Sample t.
In Samples in columns, enter Values.
Check Perform hypothesis test. In Hypothesized mean, enter 5.
Click Options. In Confidence level, enter 90.
Click OK in each dialog box.
One-Sample T: Values
Test of μ = 5 vs ≠ 5
Variable N Mean StDev SE Mean
90% CI
T
P
Values
9 4.7889 0.2472
0.0824 (4.6357, 4.9421) -2.56 0.034
Interpreting the results
The test statistic, T, for H0: m = 5 is calculated as -2.56.
The p-value of this test, or the probability of obtaining more extreme value of the test statistic by chance
if the null hypothesis was true, is 0.034. This is called the attained significance level, or p-value. Therefore,
reject H0 if your acceptable α level is greater than the p-value, or 0.034.
A 90% confidence interval for the population mean, μ, is (4.6357,4.9421). This interval is slightly wider than
the corresponding Z-interval shown in Example of 1-Sample Z.
WWW.MINITAB.COM