What is the standard deviation of 1 2 3 4 5 6 7 8 9?

2.738612788

First, find the mean (average) of all the numbers:

1+2+3+4+5+6+7+8+9 = 45

45 / 9 = 5

Mean is 5

Now take every number and calculate how far it is away from the mean, then square that number

1-5 = -4 ^2 = 16

2-5 = -3 ^2 = 9

3-5 = -2 ^2 = 4

4-5 = -1 ^2 = 1

5-5 = 0 ^2 = 0

6-5 = 1 ^2 = 1

7-5 = 2 ^2 = 4

8-5 = 3 ^2 = 9

9-5 = 4 ^2 = 16

Next, add all the results:

16+9+4+1+0+1+4+9+16 = 60

Then divide by the sample size minus 1 (n-1):

60 / 8 = 7.5

Finally, find the square root of that number:

7.5^ 0.5 = 2.738612788

Answer: 2.738612788