heyy sorry i dont really know what is the 'standard deviation' but as for the mean you go to add all the numebers together and divide them by the amount of numbers there are (7 in this scenario)
Step-by-step explanation:
21 + 29.5 + 38 + 46.5 + 55 + 63.5 + 72 = 325.5
then you divide 325.5 by the number of numbers present in the question
