Question: Distribution: Rhode Island Red Chickens

The incubation time for Rhode Island Red chicks is normally distributed with a mean of 21 days and standard deviation of approximately 1 day (based on information from World Book Encyclopedia). If 1000 eggs are being incubated, how many chicks do we expect will hatch

a.) in 19 to 23 days?

b.) in 20 to 22 days?

c.) in 21 days or fewer?

d.) in 18 to 24 days? (Assume all eggs eventually hatch.)

(Note: In this problem, let us agree to think of a single day or a succession of days as a continuous interval of time.)