Bookstores like education, one reason being that educated people are more likely to spend money on books. national data show the nationwide average educational level to be 13 years of schooling completed, with an sd of about 3 years, for persons age 18 and over.17 a bookstore is doing a market survey in a certain county, and takes a simple random sample of 1,000 people age 18 and over. they find the average educational level to be 14 years, and the sd is 5 years. can the difference in average educational level between the sample and the nation be explained by chance variation? if not, what other explanation can you give?