Question

The scores on the exam public health professionals take to be certified follows a normal distribution with a mean score of 75 points and a standard deviation of 7 points.

What is the probability someone scores between 60 and 70?

Round your answer to 4 decimal places.

Answer 1

Solution :

Given that ,

mean = = 75

standard deviation = = 7

P(60< x <70 ) = P[(60 - 75) /7 < (x - ) / < (70 - 75) /7 )]

= P(-2.14 < Z < -0.71)

= P(Z <-0.71 ) - P(Z <-2.14 )

Using z table,  

= 0.2389 -  0.0162

=0.2227