Question

The mean of 10 observation is 42 If each observation in the data is decreased by 12. Find the new mean of the data ?

Answer 1

shortcut method is 42-12=30 mean is 30. long method is first u find sum 42×10=420 and then 12×10=120 subtract them 420-120=300 and divide 300 by 10 new mean is 30