It is believed that 11% of voters are Independent. A survey asked 23 people to identify themselves as Democrat, Republican, or Independent.?

A. What is the probability that none of the people are Independent?

Probability = 

B. What is the probability that fewer than 4 are Independent?

Probability = 

C. What is the probability that more than 19 people are Independent?

Probability = 

1 Answer

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  • david
    Lv 7
    9 months ago

    Adding democrats and republicans just tries to confuse you. The question is really binomial with the 2 choices independent and not independent ... p = prob. that a person is independent = 0.11 and q = prob a person is not independent = 0.89

    select 23

    A. P(none are p) = (23C0) x 0.11^0 x 0.89^23 = 0.068544

    B. fewer than 4 .. means 0, 1 2, or 3

    .... do all 4 and add them

    P(0) .. done above

    P(1) = (23C1) x 0.11^1 x 0.89^22 = use a calcultor

    P(2) = (23C2) x 0.11^2 x 0.89^21 = use a calculator

    P(3) = (23C3) x 0.11^3 x 0.89^20 =

    .... then add all

    C. more than 19 .. means 20 or 21 or 22 or 23

    ... you can so these ... just set up loke above

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