Name: ANOVA 1: Calculating SST (total sum of squares) | Probability and Statistics | Khan Academy
Uploaded: 2016-11-19T19:12:37.000Z
Duration: 7 min 39 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

we're just really going to be doing a bunch of calculations

And hopefully, just going through those calculations

Now, the first thing I want to do in this video

And you could view it as really the numerator

So you're just going to take the distance between each

of these data points and the mean of all of these data

points, square them, and just take that sum.

We're not going to divide by the degree of freedom, which

you would normally do if you were calculating

we have to figure out the mean of all of this stuff over here.

And I'm actually going to call that the grand mean.

that it's the same thing as the mean of the means of each

So it's going to be 3 plus 2 plus 1 plus 5 plus 3 plus 4

And then 6 plus 12 is 18 plus another 18 is 36, divided by 9

And let me show you that that's the exact same thing

the mean of group 1 over here is 3 plus 2 plus 1.

That's that 6 right over here, divided by 3 data

So if you were to take the mean of the means, which

is another way of viewing this grand mean, you have 2 plus 4

plus 6, which is 12, divided by 3 means here.

or the mean of the means of each of these groups.

But either way, now that we've calculated it,

we can actually figure out the total sum of squares.

the 4 is this 4 right over here-- squared plus 2 minus 4

Now, I'll do these guys over here in purple.

Plus 5 minus 4 squared plus 3 minus 4 squared plus 4 minus 4

Now, we only have three left, plus 5 minus 4 squared

plus 6 minus 4 squared plus 7 minus 4 squared.

So up here, this is going to be equal to 3 minus 4.

It's actually negative 1, but you square it, you get 1,

plus you get negative 2 squared is 4, plus negative 3 squared.

And then we have here in the magenta 5 minus 4

So we could-- well, I'll just write the 0 there just

to show you that we actually calculated that.

And then we have these last three data points.

And then plus 7 minus 4 is 3 squared is 9.

So I have 1 plus 4 plus 9 right over here.

And then we also have another 14 right over here

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ANOVA 1: Calculating SST (total sum of squares) | Probability and Statistics | Khan Academy

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