Approximate each of these Poisson distributions with the normal distribution.

A continuity correction will be needed with each question.

1. A door to door cosmetic agent makes an average of 26 successful calls per week.

What is the probability that on a particular week she makes less than 20 successful calls?

2. The mean number of aircraft landing at an airport per hour is 38.

a. Use the Poisson formula to find the probability that 40 planes land in any one hour period.

b. Use the normal approximation to calculate the probability that 40 planes land in any one hour period.

3. The number of bacteria viewed on a slide under a microscope follows a Poisson distribution with λ = 60.

Find the probability that there are between 50 and 65 bacteria inclusive on the slide.