The data set is:
a) The variance of a data set is given by the formula:
Where s^2 is the variance and P(a_n) is the probability of the value a_n.
First, we need to calculate the mean of the data set:
Now, the variance is:
Then,
Therefore, the variance is equal to 5.6
b) As for the standard deviation, we simply need to get the square root of the variance. Then,
The standard deviation is 2.3664 approximately