In cwendorf/dgb: DGB

library(DGB)

Mean Difference from Two (Independent) Samples

ci.mean.is

Computes confidence interval for a difference in population means in a 2-group design.

Arguments: - alpha: alpha level for 1-alpha confidence - mj: sample mean in group j - sdj: sample standard deviation in group j - nj: sample size in group j

Values: - estimate, SE, df, lower limit, upper limit for both equal variance and unequal variance methods

alpha = .05
m1 = 34.2
sd1 = 5.712
n1 = 10
m2 = 41.5
sd2 = 6.451
n2 = 10
ci.mean.is(alpha, m1, m2, sd1, sd2, n1, n2)

size.ci.mean.is

Computes sample size required to estimate a population mean difference with desired precision in a 2-group design.

Arguments: - alpha: alpha level for 1-alpha confidence - var: planning value of average within-group DV variance - w: desired confidence interval width - r: desired n2/n1 ratio

Values: - required sample size per group (or n1 when r not equal to 1)

alpha = .05
var = 37.1
w = 5
r = 1
size.ci.mean.is(alpha, var, w, r)

cwendorf/dgb documentation built on May 3, 2022, 9:35 p.m.