Body Mass Data for Control & Stress Groups, Binge Eating Experiment with R

Body Mass Data for Control & Stress Groups, Binge Eating Experiment with R. Mackechnie and K. Govind

From sigmastat file: bodymass.

Body Mass, 14 June 2007

One Way Analysis of Variance Monday, June 25, 2007, 4:11:57 PM

Data source: Data 1 in Notebook 1

Normality Test: Failed (P = 0.030)

Equal Variance Test: Passed (P = 0.653)

Group Name N Missing Mean Std Dev SEM

CS 10 0 323.200 9.531 3.014

C 10 0 317.900 11.050 3.494

IS 10 0 314.000 12.481 3.947

I 10 0 313.100 10.376 3.281

R3S 10 0 316.200 5.940 1.879

R3 10 0 315.300 7.987 2.526

R7S 10 0 312.400 10.679 3.377

R7 10 0 319.500 8.303 2.626

Source of Variation DF SS MS F P

Between Groups 7 919.800 131.400 1.386 0.224

Residual 72 6826.000 94.806

Total 79 7745.800

The differences in the mean values among the treatment groups are not great enough to exclude the possibility that the difference is due to random sampling variability; there is not a statistically significant difference (P = 0.224).

Power of performed test with alpha = 0.050: 0.160

The power of the performed test (0.160) is below the desired power of 0.800.

You should interpret the negative findings cautiously.

Body Mass, 18 June 2007

One Way Analysis of Variance Monday, June 25, 2007, 4:11:09 PM

Data source: Data 1 in Notebook 1

Normality Test: Passed (P > 0.050)

Equal Variance Test: Passed (P = 0.235)

Group Name N Missing Mean Std Dev SEM

CS 10 0 353.700 12.347 3.905

C 10 0 350.000 16.316 5.160

IS 10 0 342.200 15.490 4.899

I 10 0 341.400 10.522 3.327

R3S 10 0 347.800 9.390 2.969

R3 10 0 343.200 6.106 1.931

R7S 10 0 340.100 15.029 4.753

R7 10 0 353.100 10.049 3.178

Source of Variation DF SS MS F P

Between Groups 7 2056.588 293.798 1.924 0.078

Residual 72 10995.100 152.710

Total 79 13051.688

The differences in the mean values among the treatment groups are not great enough to exclude the possibility that the difference is due to random sampling variability; there is not a statistically significant difference (P = 0.078).

Power of performed test with alpha = 0.050: 0.365

The power of the performed test (0.365) is below the desired power of 0.800.

You should interpret the negative findings cautiously.

Body Mass, 21 June 2007

One Way Analysis of Variance Monday, June 25, 2007, 4:10:14 PM

Data source: Data 1 in Notebook 1

Normality Test: Passed (P > 0.050)

Equal Variance Test: Passed (P = 0.452)

Group Name N Missing Mean Std Dev SEM

CS 10 0 371.400 15.493 4.899

C 10 0 373.100 18.083 5.718

IS 10 0 360.500 17.822 5.636

I 10 0 358.500 14.804 4.682

R3S 10 0 368.900 11.348 3.588

R3 10 0 366.000 8.219 2.599

R7S 10 0 367.600 30.895 9.770

R7 10 0 371.500 13.575 4.293

Source of Variation DF SS MS F P

Between Groups 7 1960.088 280.013 0.918 0.497

Residual 72 21950.100 304.862

Total 79 23910.188

The differences in the mean values among the treatment groups are not great enough to exclude the possibility that the difference is due to random sampling variability; there is not a statistically significant difference (P = 0.497).

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.

Body Mass, 25 June 2007

One Way Analysis of Variance Monday, June 25, 2007, 4:54:29 PM

Data source: Data 1 in body_mass

Normality Test: Passed (P > 0.050)

Equal Variance Test: Passed (P = 0.602)

Group Name N Missing Mean Std Dev SEM

CS 10 0 402.200 19.510 6.169

C 10 0 400.100 24.411 7.719

IS 10 0 383.800 19.002 6.009

I 10 0 380.200 16.884 5.339

R3S 10 0 395.400 16.494 5.216

R3 10 0 391.500 12.599 3.984

R7S 10 0 381.000 17.645 5.580

R7 10 0 398.500 15.636 4.945

Source of Variation DF SS MS F P

Between Groups 7 5498.287 785.470 2.408 0.028

Residual 72 23483.100 326.154

Total 79 28981.387

The differences in the mean values among the treatment groups are greater than would be expected by chance; there is a statistically significant difference (P = 0.028).

Power of performed test with alpha = 0.050: 0.554

The power of the performed test (0.554) is below the desired power of 0.800.

You should interpret the negative findings cautiously.

All Pairwise Multiple Comparison Procedures (Student-Newman-Keuls Method) :

Comparisons for factor: Group

Comparison Diff of Means p q P P<0.050

CS vs. I 22.000 8 3.852 0.132 No

CS vs. R7S 21.200 7 3.712 0.134 Do Not Test

CS vs. IS 18.400 6 3.222 0.217 Do Not Test

CS vs. R3 10.700 5 1.874 0.677 Do Not Test

CS vs. R3S 6.800 4 1.191 0.834 Do Not Test

CS vs. R7 3.700 3 0.648 0.891 Do Not Test

CS vs. C 2.100 2 0.368 0.796 Do Not Test

C vs. I 19.900 7 3.485 0.188 Do Not Test

C vs. R7S 19.100 6 3.344 0.183 Do Not Test

C vs. IS 16.300 5 2.854 0.268 Do Not Test

C vs. R3 8.600 4 1.506 0.712 Do Not Test

C vs. R3S 4.700 3 0.823 0.830 Do Not Test

C vs. R7 1.600 2 0.280 0.844 Do Not Test

R7 vs. I 18.300 6 3.204 0.222 Do Not Test

R7 vs. R7S 17.500 5 3.064 0.204 Do Not Test

R7 vs. IS 14.700 4 2.574 0.273 Do Not Test

R7 vs. R3 7.000 3 1.226 0.663 Do Not Test

R7 vs. R3S 3.100 2 0.543 0.702 Do Not Test

R3S vs. I 15.200 5 2.662 0.336 Do Not Test

R3S vs. R7S 14.400 4 2.521 0.290 Do Not Test

R3S vs. IS 11.600 3 2.031 0.328 Do Not Test

R3S vs. R3 3.900 2 0.683 0.631 Do Not Test

R3 vs. I 11.300 4 1.979 0.504 Do Not Test

R3 vs. R7S 10.500 3 1.839 0.400 Do Not Test

R3 vs. IS 7.700 2 1.348 0.344 Do Not Test

IS vs. I 3.600 3 0.630 0.897 Do Not Test

IS vs. R7S 2.800 2 0.490 0.730 Do Not Test

R7S vs. I 0.800 2 0.140 0.921 Do Not Test

A result of "Do Not Test" occurs for a comparison when no significant difference is found between two means that enclose that comparison. For example, if you had four means sorted in order, and found no difference between means 4 vs. 2, then you would not test 4 vs. 3 and 3 vs. 2, but still test 4 vs. 1 and 3 vs. 1 (4 vs. 3 and 3 vs. 2 are enclosed by 4 vs. 2: 4 3 2 1). Note that not testing the enclosed means is a procedural rule, and a result of Do Not Test should be treated as if there is no significant difference between the means, even though one may appear to exist.

Body Mass 28 June 2007

One Way Analysis of Variance Thursday, June 28, 2007, 1:33:57 PM

Data source: Data 1 in body_mass.SNB

Normality Test: Passed (P > 0.050)

Equal Variance Test: Passed (P = 0.746)

Group Name N Missing Mean Std Dev SEM

CS 10 0 414.100 20.426 6.459

C 10 0 418.400 26.830 8.484

IS 10 0 392.500 19.260 6.091

I 10 0 393.600 18.356 5.805

R3S 10 0 406.500 16.352 5.171

R3 10 0 407.400 15.742 4.978

R7S 10 0 393.300 20.462 6.471

R7 10 0 410.700 21.833 6.904

Source of Variation DF SS MS F P

Between Groups 7 7244.388 1034.913 2.543 0.021

Residual 72 29299.300 406.935

Total 79 36543.688

The differences in the mean values among the treatment groups are greater than would be expected by chance; there is a statistically significant difference (P = 0.021).

Power of performed test with alpha = 0.050: 0.601

The power of the performed test (0.601) is below the desired power of 0.800.

You should interpret the negative findings cautiously.

All Pairwise Multiple Comparison Procedures (Student-Newman-Keuls Method) :

Comparisons for factor: Group

Comparison Diff of Means p q P P<0.050

C vs. IS 25.900 8 4.060 0.094 No

C vs. R7S 25.100 7 3.935 0.093 Do Not Test

C vs. I 24.800 6 3.888 0.078 Do Not Test

C vs. R3S 11.900 5 1.865 0.680 Do Not Test

C vs. R3 11.000 4 1.724 0.617 Do Not Test

C vs. R7 7.700 3 1.207 0.671 Do Not Test

C vs. CS 4.300 2 0.674 0.635 Do Not Test

CS vs. IS 21.600 7 3.386 0.216 Do Not Test

CS vs. R7S 20.800 6 3.261 0.205 Do Not Test

CS vs. I 20.500 5 3.214 0.166 Do Not Test

CS vs. R3S 7.600 4 1.191 0.834 Do Not Test

CS vs. R3 6.700 3 1.050 0.739 Do Not Test

CS vs. R7 3.400 2 0.533 0.707 Do Not Test

R7 vs. IS 18.200 6 2.853 0.343 Do Not Test

R7 vs. R7S 17.400 5 2.728 0.312 Do Not Test

R7 vs. I 17.100 4 2.681 0.239 Do Not Test

R7 vs. R3S 4.200 3 0.658 0.888 Do Not Test

R7 vs. R3 3.300 2 0.517 0.716 Do Not Test

R3 vs. IS 14.900 5 2.336 0.470 Do Not Test

R3 vs. R7S 14.100 4 2.210 0.406 Do Not Test

R3 vs. I 13.800 3 2.163 0.283 Do Not Test

R3 vs. R3S 0.900 2 0.141 0.921 Do Not Test

R3S vs. IS 14.000 4 2.195 0.413 Do Not Test

R3S vs. R7S 13.200 3 2.069 0.315 Do Not Test

R3S vs. I 12.900 2 2.022 0.157 Do Not Test

I vs. IS 1.100 3 0.172 0.992 Do Not Test

I vs. R7S 0.300 2 0.0470 0.974 Do Not Test

R7S vs. IS 0.800 2 0.125 0.930 Do Not Test

A result of "Do Not Test" occurs for a comparison when no significant difference is found between two means that enclose that comparison. For example, if you had four means sorted in order, and found no difference between means 4 vs. 2, then you would not test 4 vs. 3 and 3 vs. 2, but still test 4 vs. 1 and 3 vs. 1 (4 vs. 3 and 3 vs. 2 are enclosed by 4 vs. 2: 4 3 2 1). Note that not testing the enclosed means is a procedural rule, and a result of Do Not Test should be treated as if there is no significant difference between the means, even though one may appear to exist.

Day 27 Body mass

One Way Analysis of Variance Thursday, July 19, 2007, 2:23:40 PM

Data source: Data 1 in body_mass.SNB

Normality Test: Passed (P > 0.050)

Equal Variance Test: Passed (P = 0.354)

Group Name N Missing Mean Std Dev SEM

S 40 0 472.125 31.021 4.905

NS 40 0 495.550 42.550 6.728

Source of Variation DF SS MS F P

Between Groups 1 10974.613 10974.613 7.916 0.006

Residual 78 108140.275 1386.414

Total 79 119114.887

The differences in the mean values among the treatment groups are greater than would be expected by chance; there is a statistically significant difference (P = 0.006).

Power of performed test with alpha = 0.050: 0.748

The power of the performed test (0.748) is below the desired power of 0.800.

You should interpret the negative findings cautiously.

All Pairwise Multiple Comparison Procedures (Student-Newman-Keuls Method) :

Comparisons for factor: STRESS/NO STRESS

Comparison Diff of Means p q P P<0.050

NS vs. S 23.425 2 3.979 0.006 Yes

Day 27 body mass, stressed vs non-stressed

t-test Thursday, July 19, 2007, 2:25:22 PM

Data source: Data 1 in body_mass.SNB

Normality Test: Passed (P > 0.050)

Equal Variance Test: Passed (P = 0.354)

Group Name N Missing Mean Std Dev SEM

Stressed 40 0 472.125 31.021 4.905

Nnon-stressed 40 0 495.550 42.550 6.728

Difference -23.425

t = -2.814 with 78 degrees of freedom. (P = 0.006)

95 percent confidence interval for difference of means: -40.001 to -6.849

The difference in the mean values of the two groups is greater than would be expected by chance; there is a statistically significant difference between the input groups (P = 0.006).

Power of performed test with alpha = 0.050: 0.748

The power of the performed test (0.748) is below the desired power of 0.800.

You should interpret the negative findings cautiously.

Day 27 body mass

One Way Analysis of Variance Thursday, July 19, 2007, 2:27:28 PM

Data source: Data 1 in body_mass.SNB

Normality Test: Passed (P > 0.050)

Equal Variance Test: Passed (P = 0.711)

Group Name N Missing Mean Std Dev SEM

CS 10 0 484.500 31.483 9.956

C 10 0 524.800 34.839 11.017

IS 10 0 455.900 34.001 10.752

I 10 0 467.100 32.067 10.141

R3S 10 0 483.400 23.263 7.356

R3 10 0 481.400 48.576 15.361

R7S 10 0 464.700 28.574 9.036

R7 10 0 508.900 31.200 9.866

Source of Variation DF SS MS F P

Between Groups 7 37395.188 5342.170 4.707 <0.001

Residual 72 81719.700 1134.996

Total 79 119114.887

The differences in the mean values among the treatment groups are greater than would be expected by chance; there is a statistically significant difference (P = <0.001).

Power of performed test with alpha = 0.050: 0.970

All Pairwise Multiple Comparison Procedures (Student-Newman-Keuls Method) :

Comparisons for factor: Group

Comparison Diff of Means p q P P<0.050

C vs. IS 68.900 8 6.467 <0.001 Yes

C vs. R7S 60.100 7 5.641 0.003 Yes

C vs. I 57.700 6 5.416 0.004 Yes

C vs. R3 43.400 5 4.074 0.041 Yes

C vs. R3S 41.400 4 3.886 0.037 Yes

C vs. CS 40.300 3 3.783 0.025 Yes

C vs. R7 15.900 2 1.492 0.295 No

R7 vs. IS 53.000 7 4.975 0.013 Yes

R7 vs. R7S 44.200 6 4.149 0.049 Yes

R7 vs. I 41.800 5 3.924 0.053 No

R7 vs. R3 27.500 4 2.581 0.270 Do Not Test

R7 vs. R3S 25.500 3 2.394 0.215 Do Not Test

R7 vs. CS 24.400 2 2.290 0.110 Do Not Test

CS vs. IS 28.600 6 2.685 0.412 No