Answer
There is enough evidence to conclude that at least one population mean is different from the others.
$µ_{High~Sel}=µ_{Sel}=µ_{Nonsel}=µ_{Not~Rated}\neµ_{Open-Door}$
There is enough evidence to conclude that the mean time to degree completion for students first attending open-door institutions is higher than the mean time to degree completion for students from other institutions.
Work Step by Step
$H_0:µ_1=µ_2=µ_3=µ_4=µ_5$ versus
$H_1:$ at least one population mean is different from the others
In MINITAB, enter the Highly Selective values in C1, the Selective values in C2, the Nonselective values in C3, the Open-door values in C4 and in C5 enter the Not Rated values.
Select Stat -> ANOVA -> One-Way
Select Response data are in a separate column for each factor level.
In Responses enter C1 C2 C3 C4 C5
Click Ok.
$F_0=7.03$ with a P-value $\lt0.001\ltα=0.05$
We can conclude that at least one population mean is different from the others.
Select Stat -> ANOVA -> One-Way
Select Response data are in a separate column for each factor level.
In Responses enter C1 C2 C3 C4 C5
Click Comparisons. In "Error rate for comparisons" enter 5. In "Comparison procedures assuming equal variances" select Tukey. In "Results" select the 3 options. Click OK.
Click Ok.
