My scale's data is normally distributed, except for one dimension of the scale... The overall data has a normal distribution along with several dimensions in the scale.
First, suppose that all data are normally distributed, can I use non-parametric test? Is there a rule which requires the use of parametric tests when data is normally distributed. I know parametric is more powerful but is it a problem to insist on non-parametric test?
Second, while deciding for the types of tests, should I check total scale's k-s values for deciding whether data is normally distributed or... first total, then dimensions one by one... what should one do if all dimensions are normally distributed except for one dimension?