Sunday, February 21, 2016

For Normal distribution with mean μ = 400
and standard deviation σ = 100 find probability
that x is between 340 and 714: P( 340 < x < 714)

0.3427

0.5462

0.7249

0.9140

We have mean = 400 and standard deviation of 100, now we want P(X > 619), Z = (619 - 400)/100 = 2.19

Z(2.19) = .9857, so we take 1- .9857 since the probability is greater than, so we get .0143
For the next question, mean is 400 and standard deviation is 100, want: P( 340 < x < 714)
Z = (340 - 400)/100 = -0.6 and Z = (714 - 400)/100 = 3.14

So now we find Z(3.14) and Z(-0.6) and subtract them to get the probability in between. .9992 - .2743 = .7249

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