Question

Can anyone find the missing number in the data set if the mean is 7.8? 5,8,___12,3

Answer 1

See explanation.

Explanation:

The list of numers is:

`L={5,8,x,12,3}`

We have to find the value of `x`, for which the mean is equal to `7.8`.

The mean is calculated by dividing the sum of all numbers in the set by the quantity of data:

`bar(x)=(x_1+ ... + x_n)/n`

So to find the answer we have to solve the equation:

`(5+8+12+3+x)/5=7.8`

`(28+x)/5=39/5`

`28+x=39`

`x=11`

Answer: The value of `x` for which the mean is equal to `7.8` is `x=11`