Getting Sphericity Tests for Within Subject Repeated Measure Anova (using "car" package)

Hello everyone,

I am trying to do within subjects repeated measures anova followed by the
test of sphericity (sample dataset below).
I am able to get either mixed model or linear model anova and TukeyHSD, but
have no luck with Repeated-Measures Assuming Sphericity or Separate
Sphericity Tests.
I am trying to follow example from "car" package, but it seems that I am not
getting something right.

Dataset$Sessn <- as.factor(Dataset$Sessn)

LinearModel.1 <- lm(Response ~ Sessn*Trtmt, data=Dataset)

summary(LinearModel.1)

All, good so far, but I have problem understanding "idata=" and "idesign="
functions pertaining to my example. ?Session is my repeated measure (Sessn 1
and Sessn 2 = two sessions, in reality I have more) and it is already
stacked. Any help or guidance on this matter.

Thank you, my mock dataset is below. ?Each subject has two levels of
treatment throughout four calendar days which are recoded to Session 1 and
Session 2 in order to compare treatments by the first and subsequent days of
exposure (Treatment x Session; my DV is Response; Session is repeated).

? ?Subj Trtmt Sessn Response ?1 N 1 5 ?1 D 1 6 ?1 N 2 4 ?1 D 2 7 ?2 N 1 8
2 D 1 9 ?2 N 2 2 ?2 D 2 1 ?3 N 1 4 ?3 D 1 5 ?3 N 2 6 ?3 D 2 2 ?4 N 1 5 ?4 D
1 6 ?4 N 2 4 ?4 D 2 7 ?5 N 1 8 ?5 D 1 9 ?5 N 2 2 ?5 D 2 1 ?6 N 1 4 ?6 D 1 5
6 N 2 6 ?6 D 2 2

Sincerely,

Sergios Charntikov (Sergey), MA

Behavioral Neuropharmacology Lab
Department of Psychology
University of Nebraska-Lincoln
Lincoln, NE 68588-0308 ?USA

sergioschr-at-gmail-dot-com

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