Answer
Variance is 3.2
Standard deviation is 1.79
Work Step by Step
Step 1
First find the mean of the data set which is found by adding up all the numbers and dividing by the number of numbers.
-3/2+3/8+-1+5/2=.375
.375/4=.09375
Mean equals .09375
Step 2
Variance is found by the equation
$\frac{(s1−M)^2+(s2−M)^2}{N−1}$
Where s is the sample
M is the mean and
N is the number of samples
So the final equation should look like
$\frac{(-3/2−.09375)^2+(3/8−.09375)^2+(-1−.09375)^2+(5/2−.09375)^2}{4-1}$
Which equals 3.20
3.2 is the variance
Step 3
to find the Standard deviation or Sd
you take the square root of the variance
$\sqrt (3.2)$
Which approximately equals 1.79
The Sd is 1.79