The incubation time for Rhode Island Red chicks is normally distributed with mean of 22 days and standard deviation of approximately 3 days. Of 1000 eggs are being incubated, how many chicks do we expect will hatch in 19 to 28 days

We should expect 818 chicks to hatch in 19 to 28 days

Step-by-step explanation:

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean and standard deviation , the z-score of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Normally distributed with mean of 22 days and standard deviation of approximately 3 days.

This means that

Proportion between 19 and 28 days:

p-value of Z when X = 28 subtracted by the p-value of Z when X = 19.

X = 28

has a p-value of 0.977.

X = 19

has a p-value of 0.159.

0.977 - 0.159 = 0.818

Out of 1000:

0.818*1000 = 818

We should expect 818 chicks to hatch in 19 to 28 days

2 5/8 is the final answer! : )