Bookstores like education, because national data show that 71% of college graduates have read a book in the past year, compared to 54% of thegeneral population age 18 and over. the data also show the nationwide average educational level to be 13 years of schooling completed, with an sd of about 3 years, forpersons age 18 and over. 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 averageeducational level to be 14 years, and the sd is 5 years. a. use a z - test to test for significance. what are z and p? b. compute the 68% -95%- and 99.7%-confidence intervals. c.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?