| ci.2x2.prop.bs {statpsych} | R Documentation |
Computes tests and confidence intervals of effects in a 2x2 between- subjects design for proportions
Description
Computes adjusted Wald 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 factorial design with a dichotomous response variable. The input vector of frequency counts is f = [ f11, f12, f21, f22 ], and the input vector of sample sizes is n = [ n11, n12, n21, n22 ] where the first subscript represents the levels of Factor A and the second subscript represents the levels of Factor B.
Usage
ci.2x2.prop.bs(alpha, f, n)
Arguments
alpha |
alpha level for 1-alpha confidence |
f |
vector of frequency counts of participants who have the attribute |
n |
vector of sample sizes |
Value
Returns a 7-row matrix (one row per effect). The columns are:
Estimate - adjusted estimate of effect
SE - standard error
z - z test statistic for test of null hypothesis
p - two-sided p-value
LL - lower limit of the adjusted Wald confidence interval
UL - upper limit of the adjusted Wald confidence interval
References
Price RM, Bonett DG (2004). “An improved confidence interval for a linear function of binomial proportions.” Computational Statistics & Data Analysis, 45(3), 449–456. ISSN 01679473, doi:10.1016/S0167-9473(03)00007-0.
Examples
f <- c(15, 24, 28, 23)
n <- c(50, 50, 50, 50)
ci.2x2.prop.bs(.05, f, n)
# Should return:
# Estimate SE z p LL UL
# AB: -0.27450980 0.13692496 -2.0048193 0.044982370 -0.54287780 -0.00614181
# A: -0.11764706 0.06846248 -1.7184165 0.085720668 -0.25183106 0.01653694
# B: -0.03921569 0.06846248 -0.5728055 0.566776388 -0.17339968 0.09496831
# A at b1: -0.25000000 0.09402223 -2.6589456 0.007838561 -0.43428019 -0.06571981
# A at b2: 0.01923077 0.09787658 0.1964798 0.844234654 -0.17260380 0.21106534
# B at a1: -0.17307692 0.09432431 -1.8349132 0.066518551 -0.35794917 0.01179533
# B at a2: 0.09615385 0.09758550 0.9853293 0.324462356 -0.09511021 0.28741790