What is the probability that the number of crates having small to medium-sized eggs ranges from 65 to 70?

Question

Vasu places large-sized eggs in crates that each hold 12 eggs. It is known from previous experience that 20% of all such crates contain eggs that are small to medium-sized (instead of large). A random sample of 80 egg crates are selected from those that Vasu filled.

Answer 1

mu estimate is np and sigma estimate is sqrt(p(1-p)/n)

Here n is 80, p is .2

Use the z for the range given to find the area in the normal distribution from zlow to zhigh where z = (x-μ)/σ