| ci.2x2.mean.bs {statpsych} | R Documentation |
Computes tests and confidence intervals of effects in a 2x2 between-subjects design for means
Description
Computes confidence intervals and tests 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 between-subjects design with a quantitative response variable. A Satterthwaite adjustment to the degrees of freedom is used and equality of population variances is not assumed.
Usage
ci.2x2.mean.bs(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 - estimate of effect
SE - standard error
t - t test statistic
df - degrees of freedom
p - two-sided p-value
LL - lower limit of the confidence interval
UL - upper limit of the confidence interval
Examples
y11 <- c(14, 15, 11, 7, 16, 12, 15, 16, 10, 9)
y12 <- c(18, 24, 14, 18, 22, 21, 16, 17, 14, 13)
y21 <- c(16, 11, 10, 17, 13, 18, 12, 16, 6, 15)
y22 <- c(18, 17, 11, 9, 9, 13, 18, 15, 14, 11)
ci.2x2.mean.bs(.05, y11, y12, y21, y22)
# Should return:
# Estimate SE t df p LL UL
# AB: -5.10 2.224860 -2.29227953 35.47894 0.027931810 -9.6145264 -0.5854736
# A: 1.65 1.112430 1.48323970 35.47894 0.146840430 -0.6072632 3.9072632
# B: -2.65 1.112430 -2.38217285 35.47894 0.022698654 -4.9072632 -0.3927368
# A at b1: -0.90 1.545244 -0.58243244 17.56296 0.567678242 -4.1522367 2.3522367
# A at b2: 4.20 1.600694 2.62386142 17.93761 0.017246053 0.8362274 7.5637726
# B at a1: -5.20 1.536952 -3.38331916 17.61093 0.003393857 -8.4341379 -1.9658621
# B at a2: -0.10 1.608657 -0.06216365 17.91650 0.951120753 -3.4807927 3.2807927