EXAMPLE 14.11 Comparing the Likelihood of Purchase Scores
CASE 14.1 In the moral strategy study, F=9.93. There are three populations, so the degrees of freedom in the numerator are DFG=I−1=2. The degrees of freedom in the denominator are DFE=N−1=121−3=118. In Table E, first find the column corresponding to two degrees of freedom in the numerator. For the degrees of freedom in the denominator, there are entries for 100 and 200. These entries are very close. To be conservative, we use critical values corresponding to 100 degrees of freedom in the denominator because these are slightly larger. Because 9.93 is beyond 7.41, we reject H0 and conclude that the differences in means are statistically significant, with P<0.001.
p | Critical value |
0.100 | 2.36 |
0.050 | 3.09 |
0.025 | 3.83 |
0.010 | 4.82 |
0.001 | 7.41 |