To-Do List

[4CCoxAU]

To-do list so far

• [x] calculate average SD_1 for the test values.

• [x] SD_2 does not need to be calculated to obtain an estimate of the effect size, as most of the studies use one-sample t-tests (i.e. compare x_1 / SD_1 values to a hypothetical mean, 0.50). The remaining studies report both SD_1 and SD_2.

• [x] calculate cohen's d based on mean and average SD_1.

• [x] calculate cohen's d based on t-value (when mean/sd are not present).

• [x] insert average SD_1 for studies without mean+sd/t-values (N=2). Patterson & Werker (2002), where SD_1 = 0.1404317.

• [x] calculate effect sizes for all studies.

Update, 24-09-2020:

• calculating cohen's d from t-value and from mean/SDs generates different values. I'm using the following formulae: cohen_d = (x_1-x_2) / SD_1, cohen_d2 = t / sqrt(n_1)
  • I went through the discrepant results again and found the problem. The studies comparing infants' x_1 with a baseline condition use a paired t-test. I have calculated d using means/sd in these cases.

[4CCoxAU]

• [ ] code preliminary model with the following fixed effects:
  • age, type of stimuli, native_vs_non-native, gender, exposure_phase.