Anonymous
Anonymous asked in Science & MathematicsMathematics · 3 weeks ago

Stats Help Needed?

Suppose that 78% of cell phone owners used their cell phone in store for guidance on purchasing decisions.

If 22 people are selected at random, what is the probability that

A. exactly 5 used their cell phone in store?

B. at least 12 used their cell phone in store?

C. more than 9 but at most 14 used their cell phone in store?

D. less than 16 used their cell phone in store?

1 Answer

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  • david
    Lv 7
    3 weeks ago
    Best answer

    This is a binomial problem ... p = 0.78, q = 0.22

    A 22C5 p^5 q^17 = 5.037x10^-8

    B. I'm not doing all these .. P(12) = 22C12 p^12 q^10

    P(13) = 22C13 p^13 q^9

    P(14) = 22C14 p^14 q^8 .... etc

    last P(22) = 22C22 p^22 q^0

    ... after doing all, then add them to get the anwer

    C. P(10) + ... thru P(14)

    D .. I'll bet you can do this one ...

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