size.mean {misty}

Sample Size Determination for Testing Arithmetic Means

Description

This function performs sample size computation for the one-sample and two-sample t-test based on precision requirements (i.e., type-I-risk, type-II-risk and an effect size).

Usage

size.mean(delta, sample = c("two.sample", "one.sample"),
          alternative = c("two.sided", "less", "greater"),
          alpha = 0.05, beta = 0.1, write = NULL, append = TRUE,
          check = TRUE, output = TRUE)

Arguments

delta

a numeric value indicating the relative minimum difference to be detected, \delta.

sample

a character string specifying one- or two-sample t-test, must be one of "two.sample" (default) or "one.sample".

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.

write

a character string naming a text file with file extension ".txt" (e.g., "Output.txt") for writing the output into a text file.

append

logical: if TRUE (default), output will be appended to an existing text file with extension .txt specified in write, if FALSE existing text file will be overwritten.

check

logical: if TRUE (default), argument specification is checked.

output

logical: if TRUE (default), output is shown.

Value

Returns an object of class misty.object, which is a list with following entries:

call

function call

type

type of analysis

data

matrix or data frame specified in x

args

specification of function arguments

result

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

Author(s)

Takuya Yanagida [e-mail],

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

size.prop, size.cor

Examples

#-------------------------------------------------------------------------------
# Example 1: Two-sided one-sample test
# H0: mu = mu.0, H1: mu != mu.0
# alpha = 0.05, beta = 0.2, delta = 0.5

size.mean(delta = 0.5, sample = "one.sample",
          alternative = "two.sided", alpha = 0.05, beta = 0.2)

#-------------------------------------------------------------------------------
# Example 2: One-sided one-sample test
# H0: mu <= mu.0, H1: mu > mu.0
# alpha = 0.05, beta = 0.2, delta = 0.5

size.mean(delta = 0.5, sample = "one.sample",
          alternative = "greater", alpha = 0.05, beta = 0.2)

#-------------------------------------------------------------------------------
# Example 3: Two-sided two-sample test
# H0: mu.1 = mu.2, H1: mu.1 != mu.2
# alpha = 0.01, beta = 0.1, delta = 1

size.mean(delta = 1, sample = "two.sample",
          alternative = "two.sided", alpha = 0.01, beta = 0.1)

#-------------------------------------------------------------------------------
# Example 4: One-sided two-sample test
# H0: mu.1 <= mu.2, H1: mu.1 > mu.2
# alpha = 0.01, beta = 0.1, delta = 1

size.mean(delta = 1, sample = "two.sample",
          alternative = "greater", alpha = 0.01, beta = 0.1)