Answer
Variance is 13.01
Standard deviation 3.61
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.
2.5+-5.4+4.1+-.1+-.1=1
1/5=.2
Mean equals .2
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
$\frac{(2.5−.2)^2+(-5.4−.2)^2+(4.1−.2)^2+(-.1−.2)^2+(−.1−.2)^2}{5-1}$
Which equals 13.01
13.01 is the variance
Step 3
to find the Standard deviation or Sd
you take the square root of the variance
$\sqrt (13.01)$
Which approximately equals 3.61
The Sd is 3.61