anc {pwr2ppl}

Compute Power for One or Two Factor ANCOVA with a single covariate Takes means, sds, and sample sizes for each group. Alpha is .05 by default, alternative values may be entered by user Factor A can have up to four levels, Factor B, if used, can only be two

Description

Compute Power for One or Two Factor ANCOVA with a single covariate Takes means, sds, and sample sizes for each group. Alpha is .05 by default, alternative values may be entered by user Factor A can have up to four levels, Factor B, if used, can only be two

Usage

anc(
  m1.1,
  m2.1,
  m1.2,
  m2.2,
  m3.1 = NULL,
  m3.2 = NULL,
  m4.1 = NULL,
  m4.2 = NULL,
  s1.1 = NULL,
  s2.1 = NULL,
  s1.2 = NULL,
  s2.2 = NULL,
  s3.1 = NULL,
  s3.2 = NULL,
  s4.1 = NULL,
  s4.2 = NULL,
  r,
  s = NULL,
  alpha = 0.05,
  factors,
  levelsA = NULL,
  n
)

Arguments

m1.1

Cell mean for First level of Factor A, First level of Factor B

m2.1

Cell mean for Second level of Factor A, First level of Factor B

m1.2

Cell mean for First level of Factor A, Second level of Factor B

m2.2

Cell mean for Second level of Factor A, Second level of Factor B

m3.1

Cell mean for Third level of Factor A, First level of Factor B

m3.2

Cell mean for Third level of Factor A, Second level of Factor B

m4.1

Cell mean for Fourth level of Factor A, First level of Factor B

m4.2

Cell mean for Fourth level of Factor A, Second level of Factor B

s1.1

Cell standard deviation for First level of Factor A, First level of Factor B

s2.1

Cell standard deviation for Second level of Factor A, First level of Factor B

s1.2

Cell standard deviation for First level of Factor A, Second level of Factor B

s2.2

Cell standard deviation for Second level of Factor A, Second level of Factor B

s3.1

Cell standard deviation for Third level of Factor A, First level of Factor B

s3.2

Cell standard deviation for Third level of Factor A, Second level of Factor B

s4.1

Cell standard deviation for Fourth level of Factor A, First level of Factor B

s4.2

Cell standard deviation for Fourth level of Factor A, Second level of Factor B

r

Correlation between covariate and dependent variable.

s

Overall standard deviation. Sets all cell sds equal

alpha

Type I error (default is .05)

factors

Number of factors (1 or 2)

levelsA

levels for factor A (up to four)

n

Sample Size per cell

Value

Power for One or Two Factor ANCOVA with a single covariate

Examples

anc(m1.1=.85,m2.1=2.5, s1.1 = 1.7, s2.1=1,
m1.2=0.85, m2.2= 2.5, s1.2 = 1.7, s2.2=1,
m3.1=0.0,m3.2=2.5, s3.1 = 1.7, s3.2=1,
m4.1=0.6, m4.2 = 2.5, s4.1 = 1.7, s4.2=1, r= 0.4,
n=251, factors =2,levelsA = 4)