According to the National Center for Health Statistics (2004), 22.4% of adults in the US are smokers. A random sample of 300 adults is obtained. a. Describe the sampling distribution of `hat(p)`,...

According to the National Center for Health Statistics (2004), 22.4% of adults in the US are smokers. A random sample of 300 adults is obtained.

a. Describe the sampling distribution of `hat(p)`, the sample proportion of adults who smoke.

b. In a random sample of 300 adults, what is the probability that at least 50 are smokers?

 

1 Answer | Add Yours

mathsworkmusic's profile pic

mathsworkmusic | (Level 2) Educator

Posted on

Assuming the quoted population statistic is correct, the sampling distribution of `X = 300hat(p)`, the number who smoke in a random sample of 300 adults, can be assumed to be Binomial(300,`p`= 0.224). The sampling distribution of `hat(p) = X/300`, the proportion who smoke in a random sample of 300 adults, can then be assumed to be scaled Binomial(300,`p`= 0.224) where the scale factor is 300.

Given that the sampling distribution of the count in a sample is assumed to be Binomial(300,0.224), the probability that at least 50 adults in a random sample of 300 will be found to be smokers is (using lookup tables)

`Pr(X>50) = 0.991`

a) The sampling distribution is scaled Binomial(300,0.224) where the scale factor is 300.

b) The probability that a random sample of 300 adults will contain at least 50 smokers is 0.991.

 

 

 

 

We’ve answered 318,918 questions. We can answer yours, too.

Ask a question