Hello and welcome to a video on mean and standard deviation in Excel. Today we'll be going over a
couple of different ways you can do mean and standard deviation including long-hand calculation and
also using shortcuts in Excel like functions to do the
calculations more quickly. So we'll be using two IVs today to do these examples.
The first one we'll be talking about is average, or mean, to do a mean first
we need to find the sum of all of our values.
So we'll do that really quick. And I'm using the function equals sum to find
these. Now the next step would be to divide by n,
which we have 170 observations in our data set. And we know this because
we go all the way to row 171. But we have an
index here. So we don't count that first row. So equals
our sum divided by 170. It gives us 6,396.036.
But I can also just use average and select
two IVs.
And you can see we get the same number with a lot less work.
Okay. So that's how we find the average. We can just use equals average. What
if we wanted to find standard deviation? Well, if we wanted to do this the long way, we would need to find
x minus x bar squared, which we could do over here.
Now we've already found x bar, it's this average right here.
So we're going to say equals open parentheses x minus.
And now I'm going to select x bar in a unique way. We're going to say dollar
sign j, dollar sign 3. And that's going to tell
Excel not to move from that space that we always want it to select this number
for our calculation raised to the power of
2. That upward carat symbol means raised to the power of in Excel.
So if we wanted to square something, we would do that carat too. If we want to cube something,
then it would be carat 3. We'll hit enter and I'll double click so it
goes all the way down. Now the next step in finding
a standard deviation is to sum all of our x minus x bar squared values
and then we
divide
by n minus 1 divided by 169
because remember we have 170 in our data frame and now we square root
that. So sqrt that function is square root. We're going to select that value and
we get 2018.7219. Now there is a function in excel
which will let you find the standard deviation. We're looking
for two IVs, a standard deviation. Okay and
this time it's rounded it slightly. There we go.
Looks like this one's also rounded. There we go. Now we've got
the same number for both of these results.
So obviously you're probably going to want to use the quickest way possible to do this. And that is what we expect you to do on your
homework. We want you to get comfortable using equals average and equal standard deviation. But just know
that you can absolutely do it by hand. If you really want to to or felt the need to or
if you wanted the practice doing standard deviations for something like a test coming up.
All right, that should be all you need to know about mean and standard deviation to do your homework. Have fun with with Excel.