00:01
So in this question, you want to find the variance in the standard deviation.
00:07
Well, to do that, we've got to make a little table.
00:09
You have eight data values, 3 .8, 15, or 15, 3 .7, 16 .2, 13 .2, 13 .2, 2 .4, 4 .6, and 5 .3.
00:38
And we get some totals.
00:40
You got to find the mean first, so add them up.
00:42
You get a total of 64 .2.
00:45
So our mean, x bar, is 64 .2 divided by 8 because we have eight data values, which is 8 .025.
00:58
So we need to find the data item minus the mean.
01:02
So for each one, we're going to take that data item, and the first one, 3 .8 minus 8 .0 .0.
01:08
Which is negative 4 .225.
01:27
I'm going to do that for all of them.
01:30
So 15 minus 8 .025 is 6 .975.
01:38
3 .7 minus 8 .025 is negative 4 .325 .35 is negative 4 .325 .15.
01:46
16 .2 minus 8 .025 is 8 .17 .17 .25 is 8 .17 .15 .15 .15.
01:53
15 .15 .15...