Question

1. Say 65 percent of the people in Colorado County live in the city and 35% out in the county’s suburbs. If 1000 Colorado County residents attend a conference, and they represent a random sample of residents from the entire county, what is the probability that the number of people attending from the suburbs will be fewer than 330?

Answer 1

Solution :

Given that,

p = 0.35

q = 1 - p = 1 - 0.35 = 0.65

n = 1000

Using binomial distribution,

= n * p = 1000 * 0.35 = 350

= n * p * q = 1000 * 0.35 * 0.65 = 15.0831

Using continuity correction ,

P(x < 329.5) = P((x - ) / < (329.5 - 350) / 15.0831)

= P(z < -1.36)

= 0.0869

Probability = 0.0869