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if possible, show work also, very much appreciated The random variable x represe

ID: 3209542 • Letter: I

Question

if possible, show work also, very much appreciated

The random variable x represents the number of boys in a family with three children. Assuming that births of boys and girls are equally likely, find the mean and standard deviation for the random variable x mean: 1.50, standard deviation: .87 mean: 2.25; standard deviation: .76 mean: 2.25; standard deviation: 87 mean: 1.50, standard deviation: .76 It a recent study of college students indicated that 30% of all college students had at least one tattoo. A small private college decided to randomly and independently sample 15 of their students and ask if they have a tattoo. Find the standard deviation for this binomial random variable. Round to the nearest hundredth when necessary 4.5 3.15 1.77 10.5 A literature professor decides to give a 10-question true-false quiz. She wants to choose the passing grade such that the probability of passing a student who guesses on every question is less than .10. What score should be set as the lowest passing grade? 6 7 8 9

Explanation / Answer

(6) n = 3, p = q = 1/2

= np = 1.5 and = (npq) = 0.87

Option A

(7) n = 15, p = 0.30, q = 1 - p = 0.70

= (npq) = (15 * 0.30 * 0.70) = 1.77

Option C

(8) n = 10, p = q = 1/2

P(x) = C(10, x) p^x q^(n - x) < 0.10

For x = 6 and x = 7, the above inequality is not satisfied.

When x = 8, P(8) = C(10, 8) (1/2)^8 (1/2)^(10 - 8) = 0.044 < 0.1

Option C