Table 1 Descriptive statistics for all variables
| Â | Third grade | Fifth grade | Eighth grade |
|---|---|---|---|
M (S.D.) or % | M (S.D.) or % | M (S.D.) or % | |
SES | |||
 Income ($10,000 units) | 6.1 (4.9) | 6.2 (4.9) | 8.0 (6.2) |
 Parental education |  |  |  |
  Less than high school | 8% | 7% | 7% |
  High school | 20% | 19% | 17% |
  Some college | 33% | 34% | 33% |
  Bachelor’s degree | 24% | 24% | 25% |
  Graduate degree | 15% | 16% | 18% |
Child | |||
 Female | 50% | 50% | 50% |
 Age (months) | 111.0 (4.4) | 134.6 (4.5) | 171.3 (4.4) |
 Race | |||
  White | 62% | 62% | 62% |
  Black | 10% | 10% | 10% |
  Hispanic | 17% | 17% | 17% |
  Asian | 6% | 6% | 6% |
  Other races | 5% | 5% | 5% |
Family | |||
 Married | 77% | 76% | 76% |
 Urbanicity | |||
  Rural | 16% | 15% | 15% |
  Town | 13% | 14% | 13% |
  Suburban | 35% | 35% | 35% |
  Small urban | 20% | 20% | 20% |
  Large urban | 16% | 16% | 17% |
 In-home science opportunities | 0.009 (0.78) | 0.009 (0.78) | 0.009 (0.78) |
 Out-of-home science opportunities | 0.002 (0.76) | 0.017 (0.68) | 0.013 (0.60) |
School | |||
 Type of school |  |  |  |
  Public | 79% | 80% | 80% |
  Catholic | 13% | 13% | 13% |
  Other religious | 6% | 5% | 5% |
  Other private | 2% | 1% | 2% |
 Science class | |||
  Years teaching | 14.78 (6.68) | 14.74 (5.94) | 14.51 (5.33) |
  Teacher science training | 94% | 78% | 77% |
  Science time per week | 1.38 (0.80) | 1.66 (0.80) | 1.99 (0.81) |
Academic achievement (IRT) | |||
 Science | 35.06 (9.93) | 58.90 (14.22) | 84.74 (16.05) |
 Math | 44.30 (8.96) | 86.17 (17.63) | 115.28 (21.09) |
 Reading | 56.81 (13.61) | 109.09 (20.21) | 140.91 (23.09) |