nprop {samplesizeestimator}

Estimate sample size for hypothesis testing on proportions

Description

This function computes the sample size based on two different methods i) comparing proportion with a specified (reference) value ii) comparing two independent proportions

Usage

nprop(p1, p2, alp, pwr, type = "two", alternative = "two.sided", k = 1)

Arguments

p1

hypothesized or reported proportion

p2

anticipated proportion in the population of interest

alp

level of significance or accepted level of probability of type I error

pwr

desired level of power

type

character string stating number of groups i.e. one or two (default)

alternative

a character string specifying the alternative hypothesis, must be one of two.sided (default) or one.sided

k

ratio of number of subjects in the two groups k=1 (default)

Value

a list object, the required minimum sample size along with description for reporting

Author(s)

R. Amala, Scientist-C, ICMR-VCRC, Puducherry & G. Kumarapandiyan, Asst. Prof., Madras Christian College, Chennai

Examples

nprop(p1=0.5, p2=0.4, alp=0.05, pwr=0.90, type="one",
alternative="one.sided", k=1)
nprop(p1=0.05, p2=0.15, alp=0.05, pwr=0.90, type="two",
alternative="one.sided", k=1)