In Exercises, assume that 40% of the population has brown eyes (based on data from Dr. P. Sorita at Indiana University).

Brown Eyes Groups of 600 people are randomly selected. Find the mean and standard deviation for the numbers of people with brown eyes in such groups, then use the range rule of thumb to identify the range of usual values for those with brown eyes. For such a group of 600 randomly selected people, is 200 with brown eyes unusually low or high?

Answer :

Step 1 of 2:

Given, 40% of the people has brown eyes

n = 600 , p = 40% = 0.40

The procedure yields a binomial distribution.

Where, mean = = np

= 600(0.40)

= 240

Variance = npq

= (600)(0.40)(0.60)

= 144

Standard deviation = =

= 12