Question

The height of boys in the UAE secondary schools are create or donar random what the problem of this more than 100 m 0.79 0.2140 0167

Answer 1

Consider the random variable X as

X : Height of boys

Given : mu =E(X) = Mean = 167 cm

Sigma= SD(X) = 15

$X\sim N(\mu =167, \sigma^{2} =15^{2})$

n = number of boys are randomly selected

Xbar : Average height of boys.

Required probability = $P( \bar{X}> 169)$

$=P\left ( \frac{\bar{X}-\mu }{\sigma /\sqrt{n}} > \frac{169-167}{15/\sqrt{35}} \right )$ since $Z= \frac{\bar{X}-\mu }{\sigma /\sqrt{n}} \sim N(0,1)$

=P ( Z> 0.78881)

From normal probability table

P( Z> 0.7888) = 0.2148

Correct answer - 0.2148.