Question

Suppose that x is a binomial random variable with n = 10 and p = 0.25 . find p( 4 ). write only a number as your answer. round to 4 decimal places (for example 0.1849). do not write as a percentage.

Answer 1

If you have access to a TI-83 or 84-Plus calculator, try the following command:

binompdf(10, 0.25, 4).  The output I get is 0.1460.  Thus, the probability of getting a "4" is 0.1460.

If you do not have such a calculator, you may be able to find this result in a binomial probability table.  Look for the table for n=10.  It lists the possible outcomes {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}.  In the column labeled 0.25 (the binomial probability), find the probability of getting a "4."