Which formula is used to calculate the standard deviations of sample data

Frank has $66.50 in his account on sunday. over the next week, he makes the following changes to his balance via deposits and purchases: day debit ($) credit ($) monday 60.33 80.75 tuesday 54.45 wednesday 49.20 15.00 thursday 35.40 friday 16.85 75.00 saturday 80.56 on what day does frank first get charged an overdraft fee? a. wednesday b. thursday c. friday d. saturday select the best answer from the choices provided a b c d

Can some one explain this i got sent this. is this a threat i’m scared

Using graph paper, determine the line described by the given point and slope. click to show the correct graph below.(0, 0) and 2/3