dat.bangertdrowns2004
id | numeric |
study number | author |
character |
study author(s) |
year | numeric |
publication year | grade |
numeric |
grade level (1 = elementary; 2 = middle; 3 = high-school; 4 = college) |
length | numeric |
treatment length (in weeks) | minutes |
numeric |
minutes per assignment |
wic | numeric |
writing in class (0 = no; 1 = yes) | feedback |
numeric |
feedback (0 = no; 1 = yes) |
info | numeric |
writing contained informational components (0 = no; 1 = yes) | pers |
numeric |
writing contained personal components (0 = no; 1 = yes) |
imag | numeric |
writing contained imaginative components (0 = no; 1 = yes) | meta |
numeric |
prompts for metacognitive reflection (0 = no; 1 = yes) |
subject | character |
subject matter | ni |
numeric |
total sample size of the study |
yi | numeric |
standardized mean difference | id |
The standardized mean differences given here are bias-corrected and therefore differ slighty from the values reported in the article. Also, since only the total sample size is given in the article, the estimated sampling variances were computed under the assumption that nᵢ₁ = nᵢ₁₂ = nᵢ / 2.
### load data
dat <- get(data(dat.bangertdrowns2004))
### random-effects model
res <- rma(yi, vi, data=dat)
res
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