Question

In a Gallup Survey, 90% of the people interviewed were unaware that maintaining a healthy weight could reduce the risk of stroke. If 15 people are selected at random, find the probability that at least 9 are unaware that main- taining a proper weight could reduce the risk of stroke.

Answer 1

In a Gallup Survey, 90% of the people interviewed were unaware that maintaining a healthy weight could reduce the risk of stroke. If 15 people are selected at random, find the probability that at least 9 are unaware that maintaining a proper weight could reduce the risk of stroke.

From a binomial point of view, n=15, p = 0.9, and 9<=x<=15

Using a TI calculator: the calculations goes like this;

P(9<=x<=15) = 1 - binomcdf(15,0.9,8) = 0.999689