I need to fil all of this in with the correct information. At Kirk\'s Audio Empo

Question

I need to fil all of this in with the correct information.

At Kirk's Audio Emporium, 15% of the customers buy an extended warranty for their items. For a randomly-chosen group of 20 customers, let the random variable X= the number of customers who buy an extended warranty a) Find P(X-7). What does this number represent? b) Find P(XS6). What does this number represent? c) Find P(3 sXS9). What does this number represent? d) Find and P(x-). What do these numbers represent? a) What is the correct formula to use to find P(X 7)? P(x-7) = (0.15) (Simplify your answers.)

Explanation / Answer

a) P(X = 7) = 20C7 * 0.157 * 0.8513

a) P(X = 7) = 40C7 * 0.17 * 0.933 = 0.0576

b) Option-B) P(X < 6) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6)

P(X < 6) = 40C0 * 0.10 * 0.940 + 40C1 * 0.11 * 0.939 + 40C2 * 0.12 * 0.938 + 40C3 * 0.13 * 0.937 + 40C4 * 0.14 * 0.936 + 40C5 * 0.15 * 0.935 + 40C6 * 0.16 * 0.934

= 0.9005

c) Option-D)

P(3 < X < 9) = 0.7721

d) Option-A)

= n * p = 40 * 0.1 = 4

P(X = ) = 40C * 0.1 * 0.940-

P(X = ) = P(X = 4) = 40C4 * 0.14 * 0.936 = 0.2059

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