ci.2x2.stdmean.ws: Computes confidence intervals of standardized effects in a...

In statpsych: Statistical Methods for Psychologists

Computes confidence intervals of standardized effects in a 2x2 within-subjects design

Description

Computes confidence intervals for standardized linear contrasts of means (AB interaction, main effect of A, main effect of B, simple main effects of A, and simple main effects of B) in a 2x2 within-subjects design. Equality of population variances is not assumed. An unweighted variance standardizer is used.

Usage

ci.2x2.stdmean.ws(alpha, y11, y12, y21, y22)

Arguments

alpha	alpha level for 1-alpha confidence
y11	vector of scores at level 1 of A and level 1 of B
y12	vector of scores at level 1 of A and level 2 of B
y21	vector of scores at level 2 of A and level 1 of B
y22	vector of scores at level 2 of A and level 2 of B

Value

Returns a 7-row matrix (one row per effect). The columns are:

• Estimate - estimated standardized effect

• adj Estimate - bias adjusted standardized effect estimate

• SE - standard error

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

\insertRef

Bonett2008statpsych

Examples

y11 <- c(21, 39, 32, 29, 27, 17, 27, 21, 28, 17, 12, 27)
y12 <- c(20, 36, 33, 27, 28, 14, 30, 20, 27, 15, 11, 22)
y21 <- c(21, 36, 30, 27, 28, 15, 27, 18, 29, 16, 11, 22)
y22 <- c(18, 34, 29, 28, 28, 17, 27, 21, 26, 16, 14, 23)
ci.2x2.stdmean.ws(.05, y11, y12, y21, y22)

# Should return:
#             Estimate  adj Estimate         SE           LL        UL
# AB:       0.17248839    0.16446123 0.13654635 -0.095137544 0.4401143
# A:        0.10924265    0.10415878 0.05752822 -0.003510596 0.2219959
# B:        0.07474497    0.07126653 0.05920554 -0.041295751 0.1907857
# A at b1:  0.19548684    0.18638939 0.08460680  0.029660560 0.3613131
# A at b2:  0.02299845    0.02192816 0.09371838 -0.160686202 0.2066831
# B at a1:  0.16098916    0.15349715 0.09457347 -0.024371434 0.3463498
# B at a2: -0.01149923   -0.01096408 0.08595873 -0.179975237 0.1569768

statpsych documentation built on Sept. 11, 2024, 7:42 p.m.