(gentle music)
- All right, we're going to continue our story
of measuring different things about trees.
And this time we're going to be measuring
the change in the tree height over time.
Okay, so we're saying that we took measurements
for five years for different tree types,
and we wanna see what this data means.
Let's go to insert chart.
And as usual, Google Sheets suggest the right chart.
Okay, so there are other charts available.
If you look at let's say column chart, for example.
Well, right off the bat,
this one is just arranged incorrectly.
So let's just switch the rows and the columns.
And now this is telling the story of the tree growth.
But with a column chart,
most of the emphasis is on each individual amount,
not the change between the amounts.
So it's a little bit harder to see the growth patterns
let's say, for example of the birch.
But if you switch back to the line chart,
you can see the birch moving here
and the lines which are taking up most of the space
as the change between the two points.
Now, if you feel like these lines
are a little bit close together,
let's just move this over to the right
and stretch it out a little bit.
And there you go.
It's even easier to follow that way.
You typically want the passage of time on the X axis
and the values on the Y access.
And then when you go from left to right,
which is the way that we're conditioned to read,
at least in the Western hemisphere,
you'll see the changes as you move forward in time.
Now, if you're doing this as part of a presentation
where it's combined with other charts,
you do wanna take some time to make sure
that the colors are the same.
So in this case, let's just go to customize and series.
And then if you need to change any colors,
let's just say we want to change maple,
you select that and you change the line color right here.
All right, we'll assume that those are okay for now.
But one thing that we do wanna do is,
right, don't wanna call this birch, oak, maple,
and sycamore, let's just call it,
let's just call it tree growth.
One thing that you wanna spend a lot of time on
is just making sure that it's as readable as possible.
So another thing that you can do is smooth out the lines,
because as we talked about before,
you're looking for the change between the two points.
Well, it's not really a straight change, right?
This has to be a gradual change.
So if we bring our chart editor back up,
we go to customize.
And in the chat style,
if you place a check mark in smooth,
it's moves out the lines.
Now another thing that you can do,
and we will come back to this later when it makes more sense
is that you can insert a trendline.
So if you left click on trendline this,
lighter lines are showing the mean of the values.
So it's putting in a trend to help you guess
where it's going to be in the future.
Right now that just makes too much to look at it.
All right, so let's scroll down to this series of data
and you had someone that's kind of newer
take these measurements.
So you're going to see that there's a little bit
more randomness in them.
So we'll go to insert chart.
Google Sheets knows to take this entire range
just because I've selected at least one act of cell
in this range of data, right?
And I guess that we wanted a line chart,
but in this case, we're actually gonna go
with something a little bit different,
but first we're going to come in and change name.
We'll say birch growth.
So if you look at this,
this looks kind of like a heartbeat, frankly,
and it will lead you to assume that the growth in a birch
kinda goes up and down, but trees don't get smaller, right?
They only get bigger.
So we want to illustrate this in a different way.
We're not going to use a line chart.
So we will go to set up, drop down line chart,
and come down and pick a scatter chart.
So we'll left click on scatter chart
and we'll make this a little bit bigger.
We're trying to show you a little bit better
what all these measurements mean
without overemphasizing each measurement.
And we're trying to deemphasize the fluctuation
between these points.
So now let's go back to the trendline
that we talked about earlier.
Wasn't making sense when we looked at it at first.
But if we left click on Trendline,
now you can see why you might want to do that.
All right, so it cuts through all the noise
and it tells you where the next dot is most likely to be.
At least that's how I like to think about what it's doing.
Now, there's some different things that you can do
with this trendline.
Let's stretch this out a little bit more
just so we can see the variations as we go through this.
Right now it's a linear line.
So it's going to put a straight line into here
in the best way that it can fit it.
But that may not actually be what's happening with the data.
So let's do something I think is a little bit better,
which would be a moving average.
And then this will move with the data,
but it should move less than the data should smooth it out.
But it's still too gurged, right?
So let's change the number of periods
that it's using to calculate the moving average.
And we'll just go through four.
It gets a little bit smoother,
and we'll look at six and it gets a lot smoother.
Right?
So let's use that.
And then this is shifted forward a little bit.
So let's change it from trailing to centered.
All right?
So this is intended to draw the viewer
to what is most likely the average.
And I think this line is helping us to do that.
All right?
So let's do one last thing that's kind of fun.
It's a little bit of an addition to charts,
but it's a natural extension because if you look at this,
maybe what you're trying to do is project
what the birch growth is going to be in the future.
So let's do that with a function
and we will go to the end of our data,
and what we'll do, let's just say we're looking
over the next several days, right?
So I'm going to highlight February 1st to February 8th,
I'll go into lower right hand corner of that
until the mouse turns into a plus sign,
which means I can drag this down
and just kinda put new values in there.
It recognizes the pattern and it puts new dates.
Now you'll notice it just redid the chart,
but that's just because I have some of these values
coming in here by using the random function.
And that can recalculate what are random numbers
when you change things.
So don't let that throw you off too much.
But we're going to predict some numbers here.
So we're going to look into the future
and we're going to use a function called TREND.
And the help comes up and says,
if you give it partial data,
which is a historical data here,
it's going to put new data out there
in an ideal trend, right?
So what all this fancy wording is telling you
is that it's going to use the previous values
to predict future values.
All right, so the first thing that it needs
is a known Y data.
So if you look at this graph, the Y axis is the height.
So we will select this historical data of the heights
because that's what's known.
So that's what this function needs.
And then it needs corresponding Y values.
So what dates do those heights belong to?
We'll select that area as well.
We'll hit a comma and now it wants to know
pretty much in this case,
what days do you want me to predict this for?
Okay, so it's calling that new data X,
but it's saying, what days do you want me to predict
in this situation?
So let's highlight C82 to C89,
and then just let's put in a true for the last value.
Reading what that says down there gives me a headache.
So just make it true.
And there we go.
So there's a prediction of these values,
given all the previous values.
All right, so let's look at the chart.
And I think we need to refresh this chart a little bit
because it didn't pick those up.
So we'll go to edit.
Let's go down and look at the range.
It now ends in 89.
We will edit this chart and make sure
the range goes all the way down to 89 now.
Click out of there, and here's these new lines.
So you can see now they're just based
on mathematical prediction (gentle music)
because they don't vary from the mean anymore.
So is that exactly what's going to happen?
No, of course not, right?
There's going to be some variability in it,
but this is the mathematical best guess.
Right now, we're going to look at mapping geographical data
using the built-in charts and Google Sheets.
So it should be pretty fun.
And if you wanna check it out,
I'll see you in the next video.
Thanks for watching.
It's nice to have you along.