Binomial Distribution Suppose a reading between 30 and 40 is called “very interesting” from an archaeological point of view. Let us say you take readings at n 5 12 sites chosen at random. Let r be a binomial random variable that represents the number of “very interesting” readings from these 12 sites.

(a) Let us call “very interesting” a binomial success.
Use Table A to fi nd p, the probability of success on a single trial, where p 5 P1success2 5 P130 
x 402.

(b) What is the expected value m and standard deviation s for the random variable r?

(c) What is the probability that you will fi nd at least one “very interesting” reading in the 12 sites?

(d) What is the probability that you will fi nd fewer than three “very interesting” readings in the 12 sites?