Need help with a normal distribution problem!

#1
A professor for a social class is stating that, historically, the distribution for diploma grades in the course resemble a normal distribution with a mean diploma mark of μ=61% and a standard deviation of σ=9%.
What is the probability that a random chosen diploma mark in this course will be at least 74%?
 

katxt

Active Member
#4
I always find this helpful -
Draw a picture of the normal curve.
Put a scale of z along the bottom with 0 in the middle.
Put a scale of x with 61 in the middle and the 74.
Shade the area you want.
Find how to convert x into z.
Find how to convert z into an area.
Find the area you want.