(How) can I perform multiple regression analysis with a very strongly positively
skewed variable, ideally using SPSS?
I have a dataset comprised of 206 participants been recruited on the basis
that, where faced with a choice between Option A or Option B only, they
almost always choose Option A not B. The study aims to predict why they
might (occasionally) choose Option B not A. The outcome variable is the % of
times over a 2-week period that Option B not A was chosen (i.e. % = number
of option B choices / number of choice opportunities).
Frequencies indicate that 87% of participants chose Option A on 100% of
occasions. 5% of participants chose Option B not A on 10% of occasions. Only
1% chose Option B not A on the majority of occasions.
I have a number of potential predictor/explanatory variables that I would like
to test as predictors of participants’ deviation from using Option A all of the
time. Can such an analysis be meaningfully conducted (using SPSS) with such
heavy positive skew? If so, how?
(NB - using base 10 logarithm doesn’t work - the skewness Z score, which I
understand should be less than 1.96, is 35.21, and the base 10 log reduces it
only to 14.55.)