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the mean of 10 observations is 42 . if each observations is decreased by 12 find the new mean

sum of observations/no. of observations = mean
sum of 10 observations / 10 = 42

sum of 10 observations = 420

When each of the observation is reduced by 12, then 

sum of new 10 observations = ( sum of original 10 observations ) - 12 * 10

                                            = 420 - 120 = 300

new mean = 300/10 = 30

I think 30 is the new mean.

 

 

 

 

 

 

 

  • 15
View Full Answer

The sum of all the observations will be 42 x 10 = 420. When each observation is decreased by 12, 12 x 10 = 120 will be subtracted from the whole sum. So 420 - 120 = 300. Divide 300 by 10 to get the mean as there are still 10 observations so the new mean will be 30.

Hope it helps.

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