please help and explain in detail how to do it.

I am not in a rush to get an answer so please explain in detail so I could understand. Thank you!

In order to estimate the proportion, p, of defective transistors in a lot containing 100,000

transistors, a sample of size 800 is drawn yielding 5 defective transistors.

a. Use the sample to give a point estimate for p.

b. How large a sample would be required to estimate p within 0.1% at the 95% level of

confidence?