miscor (version 0.1-0)

size.cor: Sample size determination for testing the product-moment correlation coefficient

Description

This function performs sample size computation for testing the product-moment correlation coefficient for H0: $\rho = \rho$0 based on precision requirements (i.e., type-I-risk, type-II-risk and an effect size).

Usage

size.cor(rho = NULL, delta, alternative = c("two.sided", "less", "greater"), alpha = 0.05, beta = 0.1, output = TRUE)

Arguments

rho

a number indicating the correlation coefficient under the null hypothesis, $\rho$0.

delta

minimum difference to be detected, $\delta$.

alternative

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

alpha

type-I-risk, $\alpha$.

beta

type-II-risk, $\beta$.

output

logical: if TRUE, output is shown.

Value

Returns an object of class size with following entries:

call

function call

type

type of the test (i.e., correlation coefficient)

spec

specification of function arguments

res

list with the result, i.e., optimal sample size

References

Rasch, D., Kubinger, K. D., & Yanagida, T. (2011). Statistics in psychology - Using R and SPSS. New York: John Wiley & Sons.

Rasch, D., Pilz, J., Verdooren, L. R., & Gebhardt, G. (2011). Optimal experimental design with R. Boca Raton: Chapman & Hall/CRC.

See Also

test.cor, seqtest.cor

Examples

#--------------------------------------
# H0: rho = 0.3, H1: rho != 0.3
# alpha = 0.05, beta = 0.2, delta = 0.2

size.cor(rho = 0.3, delta = 0.2, alpha = 0.05, beta = 0.2)

#--------------------------------------
# H0: rho <= 0.3, H1: rho > 0.3
# alpha = 0.05, beta = 0.2, delta = 0.2

size.cor(rho = 0.3, delta = 0.2, alternative = "greater",
         alpha = 0.05, beta = 0.2)