Performing a ttest for a population mean using raw
data
A ttest for a population mean helps a researcher answer the question:
"Is the mean of the population of measurements a particular value?"
Minitab 14 Procedure
 Select Stat >> Basic Statistics >> 1 Sample t
...
 If it is not already done so, click on the radio button labeled
"Samples in columns."
 Select the variable you want to analyze — by clicking or
by highlighting and clicking once on "Select"—
so its name appears in the box labeled "Samples in columns."
 In the box labeled "Test mean," type the assumed
value of the mean under the null hypothesis.
 Select "Options"... Ignore the box labeled "Confidence
level." For the box labeled "Alternative,"
select the direction of the alternative hypothesis (less than, not
equal, greater than). Select OK.
 Select OK. The output will appear in the session
window.
Minitab 13 Procedure
 Select Stat >> Basic Statistics >> 1 Sample t
...
 Select the variable you want to analyze — by clicking or by
highlighting and clicking once on "Select"—
so its name appears in the box labeled "Samples in columns."
 In the box labeled "Test mean," type the assumed
value of the mean under the null hypothesis.
 Select "Options"... Ignore the box labeled "Confidence
level." For the box labeled "Alternative,"
select the direction of the alternative hypothesis (less than, not
equal, greater than). Select OK.
 Select OK. The output will appear in the session
window.

Example
The US National Research Council currently recommends that females between the ages of 11 and 50 intake
15 milligrams of iron daily.
The iron intakes of a random sample of 25 such American females are found in the dataset
irondef.txt.
Is there evidence that the population of American females is, on average,
getting less than the recommended 15 mg of iron? That is, should we
reject the null hypothesis H_{0}: μ = 15
against the alternative H_{A}: μ < 15?

Minitab dialog box
Sample Minitab output
