Return to the notes for Chapter 8Problem 8.1, page 159 from Zar (1999) Output from SigmaStatt-testWednesday, September 27, 2000, 15:11:53Normality Test:Passed (P = 0.319)Equal Variance Test:Passed (P = 0.384)Group N Missingmales 7 0 females 6 0Group Mean Std Dev SEMmales 224.271 4.211 1.592 females 225.667 3.867 1.579 Difference -1.395 t = -0.618 with 11 degrees of freedom. (P = 0.549) 95 percent confidence interval for difference of means: -6.364 to 3.574 The difference in the mean values of the two groups is not great enough to reject the possibility that the difference is due to random sampling variability. There is not a statistically significant difference between the input groups (P = 0.549). Power of performed test with alpha = 0.050: 0.050 The power of the performed test (0.050) is below the desired power of 0.800. You should interpret the negative findings cautiously.Problem 8.2, page 159 from Zar (1999) Output from SigmaStatt-test Wednesday, September 27, 2000, 15:14:43Normality Test:Passed (P = 0.826)Equal Variance Test:Passed (P = 0.310)Group N Missingnorthern 7 0 southern 8 0 Group Mean Std Dev SEM northern 117.857 4.059 1.534 southern 118.125 2.997 1.060 Difference -0.268 t = -0.147 with 13 degrees of freedom. (P = 0.886) 95 percent confidence interval for difference of means: -4.212 to 3.676 The difference in the mean values of the two groups is not great enough to reject the possibility that the difference is due to random sampling variability. There is not a statistically significant difference between the input groups (P = 0.886). Power of performed test with alpha = 0.050: 0.050 The power of the performed test (0.050) is below the desired power of 0.800. You should interpret the negative findings cautiously.

Last updated on 26 September 2000.