Question

ssume that x has a normal distribution with the specified mean and standard deviation. Find the indicated probability. (Round your answer to four decimal places.)

μ = 4; σ = 2

P(3 ≤ x ≤ 7) = 

Answer 1

We need a couple of Z scores. Z₁=(3-4)/2=-0.5, and Z₂=(7-4)/2=1.5.

To find P(3) we look up Z₁ in a normal distribution table=0.3085 and P(1.5)=0.9332.

To find P(3≤x≤7)=0.9332-0.3085=0.6247.