LSM: Least Square Means

In sasLM: 'SAS' Linear Model

Least Square Means

Description

Estimates least square means using g2 inverse.

Usage

  LSM(Formula, Data, Term, conf.level=0.95, adj="lsd", hideNonEst=TRUE, 
      PLOT=FALSE, descend=FALSE, ...)

Arguments

Formula	a conventional formula of model
Data	data.frame
Term	term name to be returned. If there is only one independent variable, this can be omitted.
conf.level	confidence level for the confidence limit
adj	adjustment method for grouping, "lsd"(default), "tukey", "bon", "duncan", "scheffe" are available. This does not affects SE, Lower CL, Upper CL of the output table.
hideNonEst	logical. hide non-estimables
PLOT	logical. whether to plot LSMs and their confidence intervals
descend	logical. This specifies the plotting order be ascending or descending.
...	arguments to be passed to plot

Details

It corresponds to SAS PROC GLM LSMEANS. The result of the second example below may be different from emmeans. This is because SAS or this function calculates mean of the transformed continuous variable. However, emmeans calculates the average before the transformation. Interaction of three variables is not supported yet. For adjust method "dunnett", see PDIFF function.

Value

Returns a table of expectations, t values and p-values.

Group	group character. This appears with one-way ANOVA or Term or adj argument is provided.
LSmean	point estimate of least square mean
LowerCL	lower confidence limit with the given confidence level by "lsd" method
UpperCL	upper confidence limit with the given confidence level by "lsd" method
SE	standard error of the point estimate
Df	degree of freedom of point estimate

Author(s)

Kyun-Seop Bae [e-mail]

See Also

PDIFF, Diffogram

Examples

  LSM(uptake ~ Type, CO2[-1,])
  LSM(uptake ~ Type - 1, CO2[-1,])
  LSM(uptake ~ Type*Treatment + conc, CO2[-1,])
  LSM(uptake ~ Type*Treatment + conc - 1, CO2[-1,])
  LSM(log(uptake) ~ Type*Treatment + log(conc), CO2[-1,])
  LSM(log(uptake) ~ Type*Treatment + log(conc) - 1, CO2[-1,])
  LSM(log(uptake) ~ Type*Treatment + as.factor(conc), CO2[-1,])
  LSM(log(uptake) ~ Type*Treatment + as.factor(conc) - 1, CO2[-1,])
  LSM(log(CMAX) ~ SEQ/SUBJ + PRD + TRT, BEdata)
  LSM(log(CMAX) ~ SEQ/SUBJ + PRD + TRT - 1, BEdata)

sasLM documentation built on Oct. 2, 2024, 9:06 a.m.