posted by rene .
Suppose we have a set of blood pressures with a mean of 110 Systolic, and a sample standard deviation of 15 points. If we assume a normal distribution of Systolic blood pressures, then between what two values can we be assured 99.7% of all Systolic blood pressures will lie?
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion (.4985) between score and mean to get the Z score.
Z = (score ± mean)/SD