Sample size for a mean absolute prediction error confidence interval

Computes the sample size required to estimate a population mean absolute prediction error for a general linear model with desired confidence interval precision. Setting s = 0 gives the sample size requirement for a mean absolute deviation in a one-group design. This function assumes that the prediction errors have an approximate normal distribution.

Usage

size.ci.mape(alpha, mape, s, w)

Arguments

alpha

alpha value for 1-alpha confidence

mape

mean absolute prediction error planning value

s

number of predictor variables

w

desired confidence interval width

Value

Returns the required sample size

Examples

size.ci.mape(.05, 4.5, 5, 2)
#>  Sample size
#>           57

# Should return:
# Sample size
#          57