Question

1.mean of 15 observations is 15.if 25 is subracted from the sum of observation .find the new sum of observations
2..please see the pic and answer

Answer 1

Mean =sum of all observations/no.of observations........ Let the sum of observations be x...... 15=x/15..... x=15*15....... x=225....... 225-25= new sum..... So,new sum =200....... (II) mean = summation of (x1+x2+xn)/n (Sorry but not able to give summation symbol)

Answer 2

Answer:

mean of 27 observations = 35

Sum of 27 observations = 35×27 = 945

If 5 is subtracted from all the observations,

Sum of 27 observations = 945−27×5 = 810

New Mean =

27

810

= 30