Question

78​% of U.S. adults think that political correctness is a problem in America today. You randomly select six U.S. adults and ask them whether they think that political correctness is a problem in America today. The random variable represents the number of U.S. adults who think that political correctness is a problem in America today. Answer the questions below.

1. Find the mean of the binomial distribution ​(Round to the nearest tenth as​ needed.)
2. Find the variance of the binomial distribution. (Round to the nearest tenth as​ needed.)
3. Find the standard deviation of the binomial distribution. (Round to the nearest tenth as​ needed.)
4. Most samples of 6 adults would differ from the mean by no more than nothing. ​(Type integers or decimals rounded to the nearest tenth as​ needed.)

Answer 1

Explanation:

Let x be a random variable representing the number of U.S. adults who think that political correctness is a problem in America today. This is a binomial distribution since the outcomes are two ways. The probability of success, p = 78/100 = 0.78

The probability of failure, q would be 1 - p = 1 - 0.78 = 0.22

n = 6

a) Mean = np = 6 × 0.78 = 4.68

b) Variance = npq = 6 × 0.78 × 0.22 = 1.0

c) Standard deviation = √npq = √(6 × 0.78 × 0.22) = 1.0

d) The standard deviation is used to express the spread of the data from the mean. Therefore, most samples of 6 adults would differ from the mean by no more than 1.0