#### Compute the sample variance and standard deviation for the water absorbency data of Exercise 1.2 on page 13.

### Solution:

We know, based on our answer in Exercise 1.2, that the sample mean is .

To compute for the sample variance, we shall use the formula

The formula states that we need to get the sum of , so we can use a table to solve for every sample.

*Note: You can refer to the solution of Exercise 1.7 on how to use a table to solve for the variance. *

The variance is

The standard deviation is just the square root of the variance. That is