what is the new mean?

Question

the mean of 19 scores is 8. If a score of 10 is added, what is the new mean? please show working

Answer 1

The mean is the sum of the terms divided by the number of terms.

 

 

mean = 8

number of scores = 19

 

 

We can find the sum using the mean formula.

 

sum of scores = mean * number of scores

sum of scores = 8 * 19

sum of scores = 152

 

 

Now we add one more score to the list. 10 is added to the sum of the scores.

 

 

New mean = (152 + 10) / (19 + 1)

 

 

 

Answer 2

The mean of 19 scores is 8 implies 8 equals the sum of scores, S, divided by 19 equals 8 or S/19=8. Then S=152. If we add a score of 10 then the number of scores becomes 19+1=20 and the new sum becomes 152+10 = 162. then the new mean equals the new sum divided by the new number of scores or 162/20= 8.1. Note Michael J. below corrected my numerical error in his answer.