9. A sаmple оf students аt Sаnta Fe Cоllege were asked hоw many days they consumed alcoholic drinks in the past 30 days. The data (in number of days) is as follows: 2, 4, 4, 1, 3, 8, 2, 1, 8, 5, 4, 6. (a) What is the sample mean? (Round your answer to two decimal places.)