Answer
$F_0=0.69$ with a P-value $\gtα$. Do not reject the null hypothesis.
We can not conclude that at least one population mean is different from the others.
Work Step by Step
$H_0:µ_{Before}=µ_{After}$ versus $H_1:µ_{Before}\neµ_{After}$
In MINITAB, enter the data according to the table below.
Select Stat -> ANOVA -> General Linear Model -> Fit General Linear Model
In Responses enter C3. In Factors enter C1 C2.
Click Ok.
$F_0=0.69$ with a P-value $=0.438\gtα=0.05$
