data are thus
r1 duration
r2 duration
r3 duration
r4 duration
r5 duration
each person completes each round (r_) and I want to see if there has
been any effect of round on the recorded duration.
so I do a repeated measures ANOVA with duration as the within subjects
variable.
which says that there is a significant main effect of round
I then want to see if gender exerts any differential effect on the
round by round improvement so in SPSS add gender as a between subjects
factor.
When this happens the previously significant main effect for round is
not significant an longer, and then the round by gender interaction is
also not significant.
can anyone explain why this is occurring? Am I doing this incorrectly
Many thanks in advance
syntax is below
This is for the round effect
GLM
LgDr.0 LgDr.1 LgDr.2 LgDr.3 LgDr.4
/WSFACTOR = duration 5 Polynomial
/METHOD = SSTYPE(3)
/CRITERIA = ALPHA(.05)
/WSDESIGN = duration .
This is to look at the effect of gender
GLM
LgDr.0 LgDr.1 LgDr.2 LgDr.3 LgDr.4 BY Sex
/WSFACTOR = duration 5 Polynomial
/METHOD = SSTYPE(3)
/PLOT = PROFILE( duration*Sex )
/CRITERIA = ALPHA(.05)
/WSDESIGN = duration
/DESIGN = Sex .
The problem has been sorted
Thanks