(a) Weekly demand at a grocery store for a breakfast cereal is normally distributed with a mean of 800 boxes and a standard deviation of 75 boxes. (i) What is the probability that the weekly demand is less than 650 boxes or greater than 950 boxes?

Respuesta :

Answer:  0.0455

Step-by-step explanation:

Given : Weekly demand at a grocery store for a breakfast cereal is normally distributed .

Population mean : [tex]\mu=800[/tex]

Standard deviation : [tex]\sigma=75[/tex]

To find : Probability that the weekly demand is less than 650 boxes or greater than 950 boxes.

We first find z-score corresponds to 650 and 950.

Since [tex]z=\dfrac{x-\mu}{\sigma}[/tex]

Then , for x= 650

[tex]z=\dfrac{650-800}{75}=-2[/tex]

x=950

[tex]z=\dfrac{950-800}{75}=2[/tex]

Then , the probability that the weekly demand is less than 650 boxes or greater than 950 boxes is given :-

[tex]P(z<-2)+P(z>2)=P(z<-2)+1-P(z<2)\\\\=0.0227501+1- 0.9772498=0.0455003\approx0.0455[/tex]

Hence, the probability that the weekly demand is less than 650 boxes or greater than 950 boxes = 0.0455