Question

the mean of 25 observations is 9 if each observation increased by 4. find new mean

Answer 1

Shortcut:

If each observation is increased by x, the. mean also increases by x.

Here, each observation is increased by 4. So mean will increase by 4.

New mean = 9 + 4 = 13
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Solution:

number of observations = 25

mean = 9

Sum of observations = 25 × 9 = 225

Now, if each observation is increases by 4, increase in sum of observation = 25×4 = 100

New sum = 225 + 100 = 325

new mean = 325/25 = 13

Answer 2

Answer:

no.of observations=25

mean=9

sum of observations=25*9=225

if each pbservation is increase by 4

increase in sum of observations ,25*4=100

new sum=225+100=325

new mean=325/25=13