Table 4.
Step |
Coefficients |
Estimate |
Standard Error |
Z Value |
P Value |
Δ Deviance |
Akaike Information Criterion |
1 | Intercept | −1.983 | 0.096 | −20.76 | <.001 | 0 | 1343.5 |
2 | Point of instruction 1 | 0.026 | 0.309 | 0.08 | .93 | 11.2 | 1338.3 |
2 | Point of instruction 2 | 0.683 | 0.330 | 2.07 | .04 | ||
2 | Point of instruction 3 | 0.152 | 0.329 | 0.46 | .64 | ||
3b | ln (Run.c) | 1.972 | 0.423 | 4.66 | <.001 | 26.4 | 1313.9 |
4 | FitSum.c | −0.006 | 0.004 | −1.44 | .15 | 1.9 | 1314.0 |
5 | Age.c | 0.028 | 0.022 | 1.29 | .20 | 1.3 | 1314.4 |
Abbreviations: Age.c, centered mean of ages; Δ Deviance, change in deviance compared with the model in the previous step; FitSum.c, centered mean of the push-up and sit-up variables combined; ln (Run.c), centered mean of the natural logarithm of run time.
Points of instruction 1 through 3 are simple contrast codes for the different programs of instruction (the intercept is thus equivalent to the grand mean). Null deviance = 1643.0 with 1787 degrees of freedom. Adding the interactions of ln (Run.c), FitSum.c, and Age.c in step 6 (not shown) did not improve the fit of the model.
Denotes the best-fitting model according to Akaike information criterion and Δ Deviance (P < .05).