Question

The final scores of students in a graduate course are distributed normally with a mean of 72 and a standard deviation of 5. What is the probability that a student's score will be between 65 and 78?

Answer 1

Answer:

0.8041

Step-by-step explanation:

We know that  

μ=72  and  σ=5

and P(65<X<78)

We can determine the Z value as (X-μ)/σ

P( 65<X<78 )=P( 65-72< X-μ<78-72)

$P((65-72)/5$

$P(65$

To fine the Z values:

$P (-1.4$

From the standard normal tables:

$P (Z$

to find P ( Z<-1.4)

$P ( Z$

From the standard normal tables:

$P ( Z$

Therefore

$P(-1.4$

$P (65$