I'm doing a write up for my thesis and having trouble with forming a reference range in SPSS for medical laboratory FBC results. Without SPSS I used the formula I would use for normally distributed data: Mean +/- (1.96xStandard deviation)

For my normally distributed data I used:

Analyse - frequencies - choose variable - statistics - percentiles - 2.5 and 97.5.

I'm not sure if I should use the 2.5th and 97.5th percentiles or should I use the 5th and 95th percentiles? I'm not sure which is correct.

For my non parametric data I used the same as the normally distributed but also:

Bootstapping - 112 samples

Confidence intervals - 95%

Am I correct in doing this? Any advice would be greatly appreciated!!

Annmarie