Question 1115800
i believe the mean will be 80 and the standard deviation will remain at 15.


a simple experiment indicates that this will be the case.


assume 3 numbers, for example:


50
100
150


the mean will be 50 + 100 +150 = 300 / 3 = 100


the standard deviation will be (50-100)^2 + (100-100)^2 + (150-100)^3 = 2500 + 0 + 2500 = 5000/3 = 1666 and 2/3


add 10 points to everybody's score.


the scores becomes:


60
110
160


the mean is 60 + 110 + 160 = 330 / 3 = 110


the standard deviation is (60 - 110)^2 + (110-110)^2 + (160-110)^2 = 2500 + 0 + 2500 = 5000 / 3 = 1666 and 2/3.


the mean was raised by 10 and the standard deviation stayed the same.


here's an excel printout that shows the same thing.


the numbers were randomly generated by excel.


then the mean and the standard deviation were calculated for both the original data set and the data set where each element was raised by 10.


the mean was 10 greater and the standard deviation remained the same.


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