excel - Finding the STDEV of a Group of Number Sets -

excel - Finding the STDEV of a Group of Number Sets -

edit: clarify, i'm attempting project number of points scored particular player in nba on given night. groups below display points scored player a, player b, , player c. then, when 3 players on team combined averages 73.25. i'm trying calculate standard deviation combined points 3 players have scored. in other words, if set 3 players on team, , combime score average of 73.25 points, stdev on average based on number sets have?

i'm trying figure out standard devation of grouping of multiple subsets 1 time combined.

i have 3 sets of numbers, follows: grouping a:

9 18 27 26 avg: 20 stdev: 7.25

group b:

15 27 32 18 avg:23 stdev: 6.82

group c:

19 48 34 20 avg: 30.25 stdev: 11.84

so have standard deviation each individual group, if combine 3 groups, example, average 73.25 (the sum of of averages). how calculate standard deviation total of these sets combined?

if take stdev of every number 9.91, average of 73.25 , stdev of 9.91 doesn't seem right me. there way it?

if understanding correctly groups a,b , c players a,b , c. given think important player b averages 23 points per game standard deviation of 6.8 project scores in 16 30 point per game range. farther assuming 4 numbers given 4 games , 73.25 average average number of combined points scored 3 players in 4 games. thinking average standard deviation of 3 players combined standard deviation of game totals. give resulting standard deviation of 21 pts. meaning project combined points of 3 players anywhere 52 94 points in game. (notice first game turns out outlier game 3 players combined , players , b individually.)

excel statistics standard-deviation