Maths question - normal distribution

The question is:

The heaviest 17% of rococo apples are classified as large, and the lightest 17% are classified as small. The remainder are classified as medium. The limits within which the masses of medium rococo apples lie are 96 g and 120 g. Stating a necessary assumption, estimate the mass of the heaviest rococo apple.

Could someone please explain the method and the answer. Thank you.

Reply 1

Theloniouss

Universities Forum Helper

Any thoughts? Have you tried anything?

Reply 2

bobbuildder

Original post by Theloniouss

Any thoughts? Have you tried anything?

I have yes, the mean would be 96+120/2=108. then the mass is between 96 and 120. the slightest is 0.17 and the heaviest is 0.83. my possible formula is 0.17=96-mean/variance and 0.83=120-mean/variance. I don't know where to go from here!

Reply 3

Theloniouss

Universities Forum Helper

Original post by bobbuildder

What are you using those formulae for?

Reply 4

bobbuildder

Original post by Theloniouss

What are you using those formulae for?

Not sure, to find Z. If i am trying to find Z why is that useful?

Reply 5

Theloniouss

Universities Forum Helper

Original post by bobbuildder

Not sure, to find Z. If i am trying to find Z why is that useful?

There are a number of ways to solve this question, but using the standard normal distribution is one of them. If you are going to find Z, how is that going to help you?

Reply 6

bobbuildder

i'm really not sure. sorry, but if I could possibly see the method I can get my head around it

Reply 7

Theloniouss

Universities Forum Helper

Original post by bobbuildder

i'm really not sure. sorry, but if I could possibly see the method I can get my head around it

You need to use the inverse normal function on your calculator. I can't show you the method because I haven't answered the question, you need to figure it out for yourself.