Question

0.044 Question 5 (1 point) Provide an appropriate response. In one city, 24% ofadults smoke. In groups of size 130 of adults, what is the variance of the number that smoke ? 23.71 31.2 11.86 4.87 Question 6 (1 point) Provide an appropriate response. According to the Federal Communications Commission, 70% of all U.S. households have vcrs. In a random sample of 15 households, what is the probability that the number of households with vers is between 10 and 12, inclusive? 0.5947 0.4053 0.7 0.2061

Answer 1

5) Binomial distribution

n = 130

P(an adult smokes), p = 0.24

q = 1 - p = 0.76

Variance = npq

= 130 x 0.24 x 0.76

= 23.71

6) Binomial distribution: P(X) = nCx p^x q^n-x

P(a household has vcrs), p = 0.70

q = 1 - p = 0.3

Number of households, n = 15

P(number of households with vcrs is between 10 and 12, inclusive) = P(10)+ P(11) + P(12)

= 15C10x0.7¹⁰x0.3⁵ + 15C11x0.7¹¹x0.3⁴ + 15C12x0.7¹²x0.3³

= 0.2061 + 0.2186 + 0.1700

= 0.5947