What is the percentile rank?

Question

As reported by a recent survey, the mean height of females 20 to 29 years old is μ=64.4 inches. If the height is approximately normally distributed with σ=2.7 inches, What is the percentile rank of a 20- to 29-year-old female who is 70.2 inches tall?

Answer 1

Compute the z-score:

 

z = (x-μ)/σ

• x = data point = 70.2 inches
• μ = mean = 64.4 inches
• σ = standard deviation = 2.7 inches

 

Once you have the z-score, look up the percentile in a z-score table http://www.z-table.com/