Confidence interval for a linear contrast of proportions in a between- subjects design

Source: R/statpsych3.R

Computes an adjusted Wald confidence interval for a linear contrast of population proportions in a between-subjects design.

ci.lc.prop.bs(alpha, f, n, v)

Arguments

alpha

alpha level for 1-alpha confidence

f

vector of frequency counts of participants who have the attribute

n

vector of sample sizes

v

vector of between-subjects contrast coefficients

Value

Returns a 1-row matrix. The columns are:

  • Estimate - adjusted estimate of proportion linear contrast

  • SE - adjusted 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

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(26, 24, 38)
n <- c(60, 60, 60)
v <- c(-.5, -.5, 1)
ci.lc.prop.bs(.05, f, n, v)
#>   Estimate         SE        z           p         LL        UL
#>  0.2119565 0.07602892 2.787841 0.005306059 0.06294259 0.3609705

# Should return:
#  Estimate         SE        z           p         LL        UL
# 0.2119565 0.07602892 2.787841 0.005306059 0.06294259 0.3609705