ztest: Test for the difference of two groups' means

In sasLM: 'SAS' Linear Model

Test for the difference of two groups' means

Description

This is similar to the two groups t-test, but using the standard normal (Z) distribution.

Usage

  ztest(m1, s1, n1, m0, s0, n0, conf.level=0.95, nullHypo=0)

Arguments

m1	mean of the first (test, active, experimental) group
s1	known standard deviation of the first group
n1	sample size of the first group
m0	mean of the second (reference, control, placebo) group
s0	known standard deviation of the second group
n0	sample size of the second group
conf.level	confidence level
nullHypo	value for the difference of means under the null hypothesis

Details

Use this only for known standard deviations (or variances) or very large sample sizes per group.

Value

The output format is very similar to that of t.test.

Author(s)

Kyun-Seop Bae [e-mail]

See Also

mtest, tmtest, TTEST

Examples

  ztest(5.4, 10.5, 3529, 5.1, 8.9, 5190) # NEJM 388;15 p1386

sasLM documentation built on June 15, 2026, 9:07 a.m.