Question

On an exam, the average score is 76 with a standard deviation of 6 points What is the probability that an individual chosen at random will have a score below 67 on this exam

Answer 1

P [ X < 67 ] = 0,66,81 or 66,81 %

Explanation:

We assume Normal Distribution N ( μ ; σ ) N ( 76 ; 6 )

z score for 67 is :

z(s) = ( X - μ ) /σ

z(s) = ( 67 - 76 ) / 6

z(s) = - 9 / 6

z(s) = - 1,5

with 1,5 we fnd n z-table area undr the curve α = 0,6681

Then P [ X < 67 ] = 0,66,81 or 66,81 %