Sample size

[mattc]

How many people are needed in the mareketing study
to be 99% sure that at least one person believes the product to be
improved? (Hint: Note that P(R less than equal to 1) =.99 is equivalent
to 1 - P(0) = .99 or P (0) =.01)

[omega]

P(X>=1) = 0.99

1-P(X=0) = 0.99

P(X=0) = 1-0.99 = 0.01

(n choose 0)*0.25^0*(1-0.25)^n = 0.01

0.75^n = 0.01

n=16 approximately