ci.2x2.median.mixed: Computes confidence intervals of effects in a 2x2 mixed...

In statpsych: Statistical Methods for Psychologists

Computes confidence intervals of effects in a 2x2 mixed design for medians

Description

Computes distribution-free confidence intervals for the AB interaction effect, main effect of A, main effect of B, simple main effects of A, and simple main effects of B in a 2x2 mixed design where Factor A is the within-subjects factor and Factor B is the between-subjects factor. Effects are defined in terms of medians rather than means. Tied scores are assumed to be rare.

Usage

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

Arguments

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

Value

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

• Estimate - estimate of effect

• SE - standard error

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

\insertRef

Bonett2020statpsych

Examples

y11 <- c(18.3, 19.5, 20.1, 17.4, 20.5, 16.1)
y12 <- c(19.1, 18.4, 19.8, 20.0, 17.2, 16.8)
y21 <- c(19.2, 16.4, 16.5, 14.0, 16.9, 18.3)
y22 <- c(16.5, 10.2, 12.7,  9.9, 13.5, 15.0)
ci.2x2.median.mixed(.05, y11, y12, y21, y22)

# Should return:
#          Estimate        SE         LL         UL
# AB:        -3.450 1.6317863 -6.6482423 -0.2517577
# A:          1.875 0.8158931  0.2758788  3.4741212
# B:          3.925 1.4262367  1.1296274  6.7203726
# A at b1:    0.150 1.4243192 -2.6416144  2.9416144
# A at b2:    3.600 0.7962670  2.0393454  5.1606546
# B at a1:    2.200 1.5812792 -0.8992503  5.2992503
# B at a2:    5.650 1.7027101  2.3127496  8.9872504

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