propdiff.freq: Frequentist sample size determination for the difference...

Description Usage Arguments Details Value Author(s) References See Also Examples

Description

The function propdiff.freq returns the required sample sizes to obtain a confidence interval of given length and confidence level for the difference between two binomial proportions.

Usage

1
propdiff.freq(len, p1.estimate, p2.estimate, level = 0.95)

Arguments

len

The desired total length of the confidence interval for the proportion

p1.estimate

A point estimate for the binomial proportion for the first population

p2.estimate

A point estimate for the binomial proportion for the second population

level

The desired level of the confidence interval (e.g., 0.95)

Details

Assume that a random sample from each of two populations will be collected in order to estimate the difference between two independent binomial proportions. Assume that the best point estimates for the unknown binomial proportions in the two populations are (p1.estimate, p2.estimate), respectively. The function propdiff.freq returns the required sample sizes to attain the desired length len and confidence level level for the confidence interval for the difference between the two unknown proportions from a frequentist point of view, using a normal approximation.

Value

The required sample sizes (n1, n2) for each group given the inputs to the function.

Author(s)

Lawrence Joseph lawrence.joseph@mcgill.ca, Patrick Belisle and Roxane du Berger

References

Lemeshow S, Hosmer Jr DW, Klar J, Lwanga SK.
Adequacy of Sample Size in Health Studies. Wiley and Sons, New York, 1990.

Joseph L, du Berger R, and Belisle P.
Bayesian and mixed Bayesian/likelihood criteria for sample size determination
Statistics in Medicine 1997;16(7):769-781.

See Also

propdiff.acc, propdiff.modwoc, propdiff.woc, propdiff.mblacc, propdiff.mblalc, propdiff.mblmodwoc, propdiff.mblwoc

Examples

1
propdiff.freq(len=0.01, p1.estimate=0.15, p2.estimate=0.20)

SampleSizeProportions documentation built on May 2, 2019, 8:53 a.m.