Question

mean of 20 observation is 17 in the observation, observations 40 is replaced by 12 find the new mean

Answer 1

$<b><font face=Copper black size=4 colour=purple>$$<b><marquee direction = "up" > <h3>$Given :

Mean of 20 observations = 17

Mean = Sum of all observations / Total observations

17 = Sum of all observations / 20

Sum of all observations = 340

Now,

Incorrect observation = 40

Correct observation = 12

Difference = 40 - 12 = 38

Now,

New sum = 340 - 38 = 302

Now,

New mean = New sum / Total observations

New mean = 302 / 20

New mean = 15.1

^^"

Answer 2

mean=sum observations/number of observation
17=x1+x2------+x19+40/20
20*17=x1+x2-----+x19+40
340=x1+x2-----+x19+40
340-40=x1+x2-------+x19
300=x1+x2-----+19
300+12=x1+x2-----+x19+12
312=x1+x2-----+x19+12
312/20=15.6