statpsych (version 1.7.0)

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

Description

Computes confidence intervals for the standardized AB interaction effect, main effect of A, main efect of B, simple main effects of A, and simple main effects of B in a 2x2 mixed factorial design where Factor A is a within-subjects factor, and Factor B is a between-subjects factor. Equality of population variances is not assumed. A square root unweigthed average variance standardizer is used.

Usage

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

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

Arguments

alpha

alpha level for 1-alpha confidence

y11

vector of scores at level 1 of A and level 1 of B (group 1)

y12

vector of scores at level 1 of A and level 2 of B (group 2)

y21

vector of scores at level 2 of A and level 1 of B (group 1)

y22

vector of scores at level 2 of A and level 2 of B (group 2)

References

Bonett2008statpsych

Examples

y11 <- c(18, 19, 20, 17, 20, 16)
y12 <- c(19, 16, 16, 14, 16, 18)
y21 <- c(19, 18, 19, 20, 17, 16)
y22 <- c(16, 10, 12,  9, 13, 15)
ci.2x2.stdmean.mixed(.05, y11, y12, y21, y22)

# Should return:
#             Estimate adj Estimate        SE          LL         UL
# AB:      -1.95153666  -1.80141845 0.5407442 -3.01137589 -0.8916974
# A:        1.06061775   1.01125934 0.2797699  0.51227884  1.6089567
# B:        1.90911195   1.76225718 0.5758855  0.78039715  3.0378267
# A at b1:  0.08484942   0.07589163 0.4650441 -0.82662027  0.9963191
# A at b2:  2.03638608   1.82139908 0.2995604  1.44925855  2.6235136
# B at a1:  0.93334362   0.86154796 0.5036429 -0.05377836  1.9204656
# B at a2:  2.88488027   2.66296641 0.7477246  1.41936706  4.3503935