Question

Can someone show me how to do Mean absolute deviation

Answer 1

To find the mean of a set, add up all of the numbers and divide by how many numbers you have. For the first set:
$\mu=\frac{10.7+2.4}2=\frac{13.1}2=6.55$
For the second set:
$\mu=\frac{13.7+2.5}2=\frac{16.2}2=8.1$

To find the mean absolute deviation, (MAD) find the mean of the distances of each number from the mean.
For the first set: 
$MAD=\frac{|10.7-6.55|+|2.4-6.55|}2=\frac{4.15+4.15}2=\frac{8.3}2=4.15$
For the second set:
$MAD=\frac{|13.7-8.1|+|2.5-8.1|}2=\frac{5.6+5.6}2=\frac{11.2}2=5.6$
Note that when you only have two data points the mean is directly between them, which is why the distances are the same.

The means-to-MAD ratio is simply that, divide one by the other and that's it.
For the first set:
$6.55\div4.15=1.57831325$
For the second set:
$8.1\div5.6=1.44642857$