Answer:
The variance for the number of tasters is 4.2
Step-by-step explanation:
For each person, there are only two possible outcomes. Either they are tasters, or they are not. The probability of a person being a taster is independent of any other person. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The variance of the binomial distribution is:
It is known that 70% of the American people are "tasters" with the rest are "non-tasters". Suppose a genetics class of size 20
This means that
So
The variance for the number of tasters is 4.2