Question

Height of 10th grade boys is normally distributed with a mean of 63.5 in. and a standard

deviation of 2.9 in.
The area greater than the Z-score is the probability that a randomly selected 14-year
old boy exceeds 70 in.
What is the probability that a randomly selected 10th grade boy exceeds 70 in.?

Answer 1

P(Z>2.24) = P(70<X<1e99) = 1.25%

Explanation:

Calculate Z-score:

Z=(x-μ)/σ

Z=(70-63.5)/2.9

Z=6.5/2.9

Z=2.24

Find area greater than Z-score:

P(Z>2.24) = P(70<X<1e99) = normalcdf(70,1e99,63.5,2.9) = 0.0125

So the probability that a randomly selected 10th-grade boy exceeds 70 inches is a 1.25% chance.