Stats Help? -

For women aged 18-24, systolic bp (in mmHg) are normally distributed with a mean of 114.8 and a standard deviation of 13.1. Hypertension is commonly defined as systolic blood pressure above 140. What is the score that separates the lowest 10% systolic blood pressure from the top 90%?

Using the table at can find that 40% of the population lies 1.28 standard deviations to one side of the mean and by definition 50% of the population is on the other side of the mean. That makes the answer 114.8 - (13.1 x 1.28) = 98