Probability question

[Guest]

I need help with this one...

It's found that the number of defective parts produced per day by a certain production line are normally distributed with a mean f 4 and a standard deviation of 2.

Find the probability that

a) More than 3 defective parts are produced on a given day.
b) Between 2 and 5 defective parts are produced on a given day?

thanks

 

[galactus]

\(\displaystyle z=\frac{x-\mu}{\sigma}\)

\(\displaystyle z=\frac{3-4}{2}=\frac{-1}{2}\)

\(\displaystyle P(z>\frac{-1}{2})\).

Look them up in the Standard Normal Distribution table.

Subtract from 1.

Do the same for part b.

\(\displaystyle z=\frac{2-4}{2}\) and \(\displaystyle z=\frac{5-4}{2}\)

\(\displaystyle P(-1<z<1/2)\)

Subtract the 2 results.

 

[Guest]

thank you very much galactus...you are a star!

:lol: