Need some urgent help!

[alexandra.vo]

I'm really confused on these 2 questions

Body mass index (BMI) is your weight in kilograms divided by the square of your height in metres. BMI is used as a measure of the “appropriate” weight of a person. High BMI is a common but sometimes controversial indicator of overweight or obesity. The Centre for Health Statistics found from a very large study of all records that the BMI of young women (age 20 to 29) in the USA is distributed approximately Normal with a mean of 26.5 and standard deviation of 6.4.

i) Young women with BMI over 30 are often classified as “obese”. What percentage of these young women would be classified as “obese” by this criterion?
I got a z-score of 0.55 and then 1- SD(0.55)=0.71. Therefore 71% are classified as obese?

ii) What is the third quartile of the BMI of young women in the USA?
haven't attempted need some help!

 

[Harry_the_cat]

Q1. Have you drawn a diagram of the normal curve and marked in the area representing the percentage you are trying to find? Does your answer of 71% seem reasonable? Would you expect the answer to be more that 50%? Rethink your answer.
Q2.What is your understanding of what the "third quartile" means? Can you represent it on a diagram of a normal curve?