anova and intercept

My usual advice on getting nonstandard F tests out of anova() is to fit the models explicitly and compare.

So how about this?

fit1 <- lm(diff(extra,10) ~ 1, sleep)
fit0 <- update(fit1, ~ -1)
anova(fit0, fit1)

-pd

On 26 Dec 2022, at 13:49 , Gabor Grothendieck <ggrothendieck at gmail.com> wrote:

Suppose we want to perform a paired test using the sleep data frame
with anova in R.  Then this works and gives the same p value as
t.test(extra ~ group, sleep, paired = TRUE, var.equal = TRUE)

  ones <- rep(1, 10)
  anova(lm(diff(extra, 10) ~ ones + 0, sleep)

This gives output but does not give an F test at all.

  ones <- rep(1, 10)
  anova(lm(diff(extra, 10) ~ 1, sleep)

Maybe there should be some way to force an F test to be produced for
the intercept in anova for consistency with t.test so that the second
code can be used.


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