The weights of pink salmon in a fishery are normally distributed, with a mean of 3.25 pounds and a standard deviation of 0.25 pounds.
What is the probability that a salmon weighs between 2.95 pounds and 3.95 pounds?
A) 0.12
B) 0.38
C) 0.62
D) 0.88

Respuesta :

Answer:

0.88

Step-by-step explanation:

Given : The weights of pink salmon in a fishery are normally distributed, with a mean of 3.25 pounds and a standard deviation of 0.25 pounds.

To Find :  What is the probability that a salmon weighs between 2.95 pounds and 3.95 pounds?

Solution:

We will use z score to find  the probability that a salmon weighs between 2.95 pounds and 3.95 pounds

Formula : [tex]z=\frac{x-\mu}{\sigma}[/tex]

[tex]\mu = 3.25\\\sigma = 0.25[/tex]

At x = 2.95

[tex]z=\frac{2.95-3.25}{0.25}[/tex]

[tex]z=-1.2[/tex]

Refer the z table for p value

P(Z<-1.2) =0.1151

At x = 3.95

[tex]z=\frac{3.95-3.25}{0.25}[/tex]

[tex]z=2.8[/tex]

Refer the z table for p value

P(Z<2.8) =0.9974

P(2.95<x<3.95)=P(-1.2<z<2.8)=P(z<2.8)-P(z<-1.2) = 0.9974-0.1151 = 0.88

Hence the probability that a salmon weighs between 2.95 pounds and 3.95 pounds is 0.88