summary1way: One-way Analysis of Variance Summary

In s20x: Functions for University of Auckland Course STATS 201/208 Data Analysis

One-way Analysis of Variance Summary

Description

Displays summary information for a one-way anova analysis. The lm object must come from a numerical response variable and a single factor. The output includes: (i) anova table; (ii) numeric summary; (iii) table of effects; (iv) plot of data with intervals.

Usage

summary1way(
  fit,
  digit = 5,
  conf.level = 0.95,
  inttype = "tukey",
  pooled = TRUE,
  print.out = TRUE,
  draw.plot = TRUE,
  ...
)

Arguments

fit	an lm object, i.e. the output from lm.
digit	decimal numbers after the point.
conf.level	confidence level of the intervals.
inttype	three options for intervals appeared on plot: 'hsd','lsd' or 'ci'.
pooled	two options: pooled or unpooled standard deviation used for plotted intervals.
print.out	if TRUE, print out the output on the screen.
draw.plot	if TRUE, plot data with intervals.
...	more options.

Value

Invisibly returns a list containing the one-way ANOVA summary components used in the printed teaching output. The list contains:

Df	degrees of freedom for between groups, within groups, and total.
Sum of Sq	sum of squares for between groups, within groups, and total.
Mean Sq	mean squares for between groups and within groups.
F value	the one-way ANOVA F statistic.
Pr(F)	the P-value associated with the F test.
Main Effect	the grand mean of the response.
Group Effects	group deviations from the grand mean.

The printed ANOVA table, numeric summary, effects table, and optional plot are the primary teaching interface. The returned list is invisible so classroom use can focus on the printed output while programmatic callers can still inspect the computed values.

See Also

summary2way, anova, aov, dummy.coef, onewayPlot

Examples

## Computer questionnaire data:
data(computer.df)
computer.df = within(computer.df, {
    selfassess = factor(selfassess)
})
computer.fit = lm(score ~ selfassess, data = computer.df)
result = summary1way(computer.fit)
result

s20x documentation built on July 1, 2026, 9:06 a.m.