PLEASE HELP Weekly wages at a certain factory are
normally distributed with a mean of
$400 and a standard deviation of $50.
Find the probability that a worker
selected at random makes betweenh
$250 and $300.

PLEASE HELP Weekly wages at a certain factory are normally distributed with a mean of 400 and a standard deviation of 50 Find the probability that a worker sele class=

Respuesta :

Answer: 0.0215 .

Step-by-step explanation:

Let X denotes the weekly wages at a certain factory .

It is normally distributed , such that

[tex]X\sim N(\mu=400,\ \sigma= 50)[/tex]

Then, the probability that a worker  selected at random makes between

$250 and $300:

[tex]P(250<X<300)=P(\dfrac{250-400}{50}<\dfrac{x-\mu}{\sigma}<\dfrac{300-400}{50})\\\\=P(\dfrac{-150}{50}<z<\dfrac{-100}{50})\ \ [z=\dfrac{x-\mu}{\sigma}]\\\\=P(-3<z<-2)\\\\=P(z<-2)-P(z<-3)\\\\=1-P(z<2)-(1-P(z<3))\\\\=P(z<3)-P(z<2)\\\\=0.9987-0.9772\\\\=0.0215[/tex]

Hence,the required probability = 0.0215 .