ci.2x2.prop.bs: Computes tests and confidence intervals of effects in a 2x2...

In statpsych: Statistical Methods for Psychologists

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.

For more details, see Section 2.14 of Bonett (2021, Volume 3)

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

• p - two-sided p-value

• LL - lower limit of the adjusted Wald confidence interval

• UL - upper limit of the adjusted Wald confidence interval

References

\insertRef

Bonett2021statpsych

\insertRef

Price2004statpsych

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 -2.0048 0.04498 -0.54287780 -0.00614181
# A:       -0.11764706 0.06846248 -1.7184 0.08572 -0.25183106  0.01653694
# B:       -0.03921569 0.06846248 -0.5728 0.56678 -0.17339968  0.09496831
# A at b1: -0.25000000 0.09402223 -2.6589 0.00784 -0.43428019 -0.06571981
# A at b2:  0.01923077 0.09787658  0.1965 0.84423 -0.17260380  0.21106534
# B at a1: -0.17307692 0.09432431 -1.8349 0.06652 -0.35794917  0.01179533
# B at a2:  0.09615385 0.09758550  0.9853 0.32446 -0.09511021  0.28741790

statpsych documentation built on Jan. 13, 2026, 1:07 a.m.