Question

standard deviation problems​

Answer 1

Answer:

The standard deviation is given by the formula:

Standard Deviation

s means 'standard deviation'.

S means 'the sum of'.

x bar means 'the mean'

Example

Find the standard deviation of 4, 9, 11, 12, 17, 5, 8, 12, 14

First work out the mean: 10.222

Now, subtract the mean individually from each of the numbers given and square the result. This is equivalent to the (x - x bar)² step. x refers to the values given in the question.

x 4 9 11 12 17 5 8 12 14

(x - x bar )2 38.7 1.49 0.60 3.16 45.9 27.3 4.94 3.16 14.3

Now add up these results (this is the 'sigma' in the formula): 139.55

Divide by n. n is the number of values, so in this case is 9. This gives us: 15.51

And finally, square root this: 3.94