Variability

Variability is finding the standard deviation of a set of data and to convert data to standard values.
Standard deviation- the amount the largest and smallest numbers are away from the mean
Mean- average of a given set of numbers. You find this by adding up all numbers then dividing by the numbers of numbers given.
Statistic- a number that describes some characteristic of a set of data.
Median-the middle number in a set of numbers. If given two middle numbers you must find the mean of these to find the median.
Mode- the number or numbers that they are most of in any given set of numbers.

To find standard deviaton you must use the following formula: s = square root of sum Xi^2 / n - X^2.
N= number of numbers
Xi= given numbers
X=mean of numbers

EX1 find standard deviation of 3 5 6 7 9

Xi Xi^2
3 9
5 25
6 36
7 49
9 81
Now add all squared answers and get 200. Now plug into formula.
Get mean 3+5+6+7+9/5 = 6

sqaure root of 200/5 - 6^2 = square root of 4 = 2