Question

A set of data has the values 34, 40, 42, 48, and 70. If the outlier of 70 is removed, what is the mean absolute deviation of the remaining four values?

3.2
4
11.2
14

Answer 1

The average of the remaining 4 numbers is 41, so their MAD is ...
  (7+1+1+7)/4 = 4.

Answer 2

After the outlier is removed the data set is 30, 40, 42, 48.

The mean of the data is $\mu=\frac{30+40+42+48}{4} =\frac{164}{4} =41$.

The mean absolute deviation of $n$ data is $MAD=\frac{\sum _{i=1}^n|x_i-\mu| }{n}$.

Here substituting the data values,

$MAD=\frac{|34-41|+|40-41|+|42-41|+|48-41| }{4}=4$.

Correct choice is (4).