PLEASE HELP & EXPALIN! THANK YOU <3
In a particular workday, the number of coffee consumed by each employee in the head office of a company was counted. The results are summarized in the following table:

number of cups of coffe: 0, 1, 2,3,4,5
frequency: 4,6,10,15,12,8

Calculate the mean number of coffee cups consumed and the standard deviation.