The taste test for PTC (phenylthiourea) is a common class demonstration in the study of genetics. It is known 70% of the American people are "tasters" and 30% are "non-tasters." Suppose a genetics class of size 20 does the test to see if they match the U.S. percentage of "tasters" and "non-tasters." (Assume the assignment of students to classes constitutes a random process.)
For the random variable x, the number of "non-tasters" in the class,
Find P(3