For a population of μ = 70 and σ = 20, find the z-score and percentile rank for each of the following X scores: 80, 100, 65, 40.

Answer 1

z=(x-μ)/σ

Find the p-value of each z-score by looking it up in the z chart.

It'll help you determine the percentile rank if you draw the normal distribution curve.

http://www.mathsisfun.com/data/standard-normal-distribution-table.html

Answer 2

μ = 70 and σ = 20