During the 2009 tax filing season 158 of all individual US t

During the 2009 tax filing season, 15.8% of all individual U.S. tax returns were prepared by H&R Block. For a random selection of 3 tax returns, describe a. The probability that no more than 1 return was prepared by H&R Block. b. The expected number of returns that were prepared by H&R Block.

Solution

During the 2009 tax filing season, 15.8% of all individual U.S. tax returns were prepared by H&R Block. For a random selection of 3 tax returns, describe

a. The probability that no more than 1 return was prepared by H&R Block.

p=0.158

n=3

P( x <=1) =P ( x=0)+P(x=1) = 0.5969+ 0.3360

=0.9329

The required P= 0.9329

b. The expected number of returns that were prepared by H&R Block.

Expectation = np = 3*0.158 =0.474