size.ci.etasqr {statpsych}

Sample size for an eta-squared confidence interval

Description

Computes the sample size required to estimate an eta-squared coefficient in a one-way ANOVA with desired confidence interval precision. Set the planning value of eta-squared to about 1/3 for a conservatively large sample size.

Usage

size.ci.etasqr(alpha, etasqr, groups, w)

Arguments

alpha

alpha level for 1-alpha confidence

etasqr

planning value of eta-squared

groups

number of groups

w

desired confidence interval width

Value

Returns the required sample size for each group

Examples

size.ci.etasqr(.05, .333, 3, .2)

# Should return:
# Sample size per group 
#                    63