Table 3.
Linear regression analysis of Peabody Developmental Motor Scales-Second Edition total motor standard scores by season and Fast Fourier Transform signals at 6 months and 12 months, respectively.
| Time and variable | Estimate (SE) | t test (df) | P value | |
| 6 months | ||||
|
|
(intercept) | 50.10 (0.56) | 89.52 (155) | <.001 |
|
|
spring | 0.48 (0.85) | 0.56 (155) | .58 |
|
|
summer | 4.48 (0.82) | 5.43 (155) | <.001 |
|
|
autumn | 4.06 (0.89) | 4.54 (155) | <.001 |
| 12 months | ||||
|
|
(intercept) | 45.52 (1.29) | 35.25 (96) | <.001 |
|
|
summer | 1.66 (1.58) | 1.05 (96) | .30 |
|
|
half daya | 0.19 (0.09) | 2.10 (96) | .04 |
|
|
one-third daya | 0.31 (0.09) | 3.55 (96) | <.001 |
|
|
summer: one-third daya | -0.48 (0.16) | −3.00 (96) | .004 |
aThe Fast Fourier Transform signals were multiplied by 10,000 in regression models, so that the estimated effect sizes were for every 10,000-unit increase in the Fast Fourier Transform signals.