Suppose that in your city 31 of the voters are registered as

Suppose that in your city 31% of the voters are registered as Democrats, 34% as Republicans, and 15% as members of other parties. Voters not aligned with any official party are termed Independent. You are conducting a poll by calling registered voters at random. In your first three calls, what is the probability that you talk to a) all Republicans? b) no Democrats? c) at least one Independent? a) The probability of calling all Republicans is . (Round to three decimal places as needed.) b) The probability of calling no Democrats is . (Round to three decimal places as needed.) c) The probability of calling at least one Independent is . (Round to three decimal places as needed.)

Solution

a)

the probability of calling all republicans

= 34% * 34% * 34%

= 0.039

b)

probability of calling no democrats

= (1-0.31) * (1-0.31) * (1-0.31)

= 0.329

c)

probability of calling at least one independent

= 1 - probability of calling no independent

= 1 - (1-0.20) (1-0.2) (1-0.2)

= 1 - 0.008

= 0.992