Question

The sum of 10 observation is 80.If half of the data is added by two and rest of is subtracted by 1 then find the correct mean?​

Answer 1

Answer:

84

Step-by-step explanation:

LET SUM= {S}

then S = 800

NOW,

800 + 40(2) -40(1) =S'

S' =840

NEW MEAN = S'/10

=84

since no. of terms are same

therefore there are 10 terms

Answer 2

Given,

Mean = 80

Total number of observations = 10

To Find,

If half of the data is added by two and the rest is subtracted by 1 then the correct mean =?

Solution,

Mean = The Sum of observations / Total number of observations

Mean = 80 = The Sum of observations / 10

The Sum of observations  = 80*10 = 800

The Sum of observations(S) = 800

Now, half of the data is added by two which means 5[10/2=5]  observations are added with 2.

The sum of observations is added with = 2 * 5 = 10

The rest of the observations are subtracted by 1

the rest observations = 10 - 5 = 5

The sum of observations is subtracted with = 5 * 1 = 5

The total sum of observations  = 800 + 10 - 5 = 805

The new mean = 805 / 10 = 80.5

Hence, the correct mean is 80.5.