1.06 Variance and standard deviation

Question 1

Variance

Answer 1

Another way of measure of data variability is to use variance (S²)and standard deviation. The main benefit of using this is that take into account ALL the values of a variable.

Larger variance => Larger variability => the more the values are spread out around the mean.

S² = Σ (x - x¯)²/ n-1

Sum of all squared values as result of subtraction mean (average value) from each value AND divided by number of values minus 1.

Question 2

Standard deviation

Answer 2

S = Sq (Σ (x - x¯)²/ n-1)

Sum of all squared values as result of subtraction mean (average value) from each value AND divided by number of values minus 1.

Standard deviation - the average distance of an observation from the mean (average).