Question

Nine percent of americans say they are well informed about politics in comparison to most people. You randomly sample 200 americans and ask if they believe that they are well informed about politics in comparison to most people. What is the probability that less than 8% of the people sampled will answer yes to the question?

Answer 1

Answer:

Step-by-step explanation:

Using normal distribution

z = (x - mean) / standard deviation

Nine percent of americans say they are well informed about politics in comparison to most people.

That means probability of success is p =9/100 = 0.09,

then probability of failure is

q = 1-p =1 -0.09= 0.91

n = number of sample = 200

x=(8% of 200) = 0.08×200 =16

mean = np = 200×0.09= 18

Standard deviation = npq = 200×0.09×0.91= 16.38

We are looking for the probability that less than 8% of the people sampled will answer yes to the question

8% of 200 = 16

P (x greater than 16) =P(x lesser than/equal to 15)

z = 15-18 /16.38 = -3/16.38

= -0.18

Looking at the normal distribution table

P(x greater than 16) = 0.5714