
Title:
SD of Karma Points per Post  Intro to Descriptive Statistics

Description:

This one probably took you a little longer to figure out, and that's okay. So,

you remember that the first thing we have to do is find the deviation from the

mean for each of these values. So, let's do it in cell B1. We found that the

mean was approximately 12.96. So, I'll write equals A1 minus 12.96. And that

will give us the deviation of the first value from the mean. Now, we'll copy

this so that we don't have to write it in every cell. And then, if you go to

cell A1 and push Cmd+Down, at least on a Mac keyboard, and then we'll go to cell

B200 and then push Cmd+Shift+Up Arrow key, then you should have the whole column

B highlighted. Now, write Cmd+V and then you have all of the deviations for each

of those values. Something else that you may have done in which I taught you

before, was going to this corner until you see the plus and then dragging it

down. And if you did that, that's perfectly fine. These are just some keyboard

shortcuts that make our life a little easier. So, in column C now, let's square

each of the deviations, so we'll write equals B1 carrot 2, which means squared,

and then again, we'll Copy cell C1, go to cell B1, push Cmd+Down Arrow key, to

go to the bottom. Go to cell C200, push Cmd+Shift+Up Arrow key, so that we have

all of column C highlighted, and then, Cmd+V. And now, we have all of our

squared deviations. So, what's the next thing we do? We have to sum them up. So,

let's do that in cell D1, equals sum of C1 colon C200. So, we added up our score

deviations and now this time, and this is where the sample standard deviation

differs from the population standard deviation, we'll divide this by n minus 1,

which is 199 equals D1 divided by 199. And then, our last step is to take the

square root, equal sqrt of D2. So, we get that our sample standard deviation is

approximately 4.76, and this is our best estimate of the population standard

deviation.