OK.
Mr. Tarrou here.
I'm continuing my new series of videos to help you learn how to learn the TI-NSPIRE.
[haha] I am learning these as I go.
So I am now going to attempt to make a capture video off my computer with the faceplate just
as an outline because I realized it was very hard to see my black curser pointer over the
black calculator which is how they look in real life.
So let's see if this works any better.
Please give me some feedback.
Ok.
We are going to make some more statistics plots.
Today we are going to take a look at histograms, box plots, and dot plots.
So we are going to open up a new document.
We are going to have to add some data to the calculator if we are going to be able to make
any graphs at all.
So we are going to do 4, Add Lists or Spreadsheets, and with a TI-NSPIRE you do need to name the
columns as you put in the data.
These are generic data just to, you know, show you how to use your calculator so I am
just going to call this x.
And we are going to come down here.
By the way, as you see this cursor move around, if you have not seen one of my other videos
yet, all of this cursor moving you would be moving your finger on the touch pad here and
moving it around... and pushing down the center of the touch pad and making it click.
That is your selection process.
Or, you could hit enter.
But, if you want to select an item with your cursor, then you would need to press down
and actually make the center of that touch pad click.
Ok, let's put in some numbers so that we can just make a histogram and see what it looks
like.
Here, and of course you can do one...
I am going to put in some generic numbers.
I am not going to keep moving my finger back and fourth.
I am just going to use my number pad here on my keyboard.
So we have got a couple of ones, four two's... so 2, 2, 2, 2.
And we will put in eight 3's.
Um, some 4's..
Maybe three 4's.
A couple of 5's.
And some 6's.
Let's skip out and make sure we have a nice outlier here.
10, and 13.
Ok.
So we have some data in our calculator.
How do we display that in a histogram?
Well, once your data is in the calculator in a list that you have named.
If you are working in Statistics all of these problems are related to real life applications.
It would be nice if you actually typed the whole name in there, or at least enough to
tell what the variable is and not just a generic x and y.
Ok.
To add a page in your calculator you want to do Control Page, and Add Data & Statistics
page.
It is number 5, so if you want you can just come down here and hit 5.
But if you are already using your cursor and you are up here... 5.
Ok.
So when you go to make a scatter plot you get just a window of random points.
We only put in one column of data so this is univariate quantitative data.
We are going to come to the x axis and click Add a Variable.
I only put one in so there is not much to choose from.
Just like that everything starts to move around and we have a dot plot.
And I just put in whole numbers and very small and you can see it as a...
I meant to look at making it more like a right skewed distribution.
Let me add another 7 and 8 here.
I am going to go back to this first page.
I can click here with my... by moving me finger over the touch pad or I can do control left
click on the touch pad and move back a page.
Let's add in another 7 and an 8.
And enter.
And then come back here and you can, with your finger on the touch pad, hit 1.2 or control
right click to move to the right.
Now we have a nice right skewed distribution.
And a couple of outliers.
This is a dot plot.
If I want to change this to a histogram.
I hit menu, plot type, and choose histogram instead of Dot Plot.
That is what is used right now.
This is not highlighted and that is because this is a dot plot.
Well I guess I cannot really say that, because it is not a bar graph or a pie chart either.
But, in this top section this is your univariate quantitative data selections and the dot plot
is the current one.
Let's make it a histogram.
Histograms pretty much just makes a bunch of bars right over those stacks of dots.
Histograms will have the classes touching to show no space between those class intervals,
since you don't leave any numbers out.
An empty group is just a class that has no data in it.
That is a lot of intervals.
Now with a histogram you do want to have about, or at least five intervals.
And this is nice and I like it actually.
But if you want to make these intervals wider, you can hit Menu and Plot Properties, and
under Histogram Properties.
Let me hit the escape button.
That window popped open too quickly.
Under histogram properties you can change the histogram scale from percents to density.
This would be a relative frequency.
Percents in statistics is called Relative Frequencies.
We want that to go back to counts.
Actually it does not really matter if it is or not.
But I want to show you how to make that go back to counts.
Plot Properties...
Histogram...
Scale... and go to Density.
That is your....
Or Frequency, excuse me.
Your frequency histogram.
That is counts.
Frequency is counts.
Relative frequency is percents.
If I go back to Menu again, and go back to Plot Properties again, the Bin Setting will
allow you to change the width of those bars.
Now I don't think the width of 2 is all that great for this set of data.
I don't know why I would want my Alignment to be .5 if I am putting all whole numbers
in.
So let's make that 0 and hit ok.
Well now the..
I still see this nice right skewed distribution.
The fact that those were outliers is kind of hidden now.
But, the bar goes off the top of the screen.
So you can hit Menu, Zoom, and Fit to Data.
And now here is our right distribution.
Now with the count counting by 2 you don't see how those were outliers like you did when
the class width was 1.
And sometimes that just happens.
Maybe I did not make them that far out... made them as far out as I thought.
And your decision on what the class width is going to be will of course, as you can
see, change slight the look of your histograms.
So that is how you make a histogram.
Again, that is how you change the property, bin, and how you change the width of your
classes to show...
To give you the number of bars you would like to see in your histogram.
Now how do you make a box plot.
You might have noticed that it was in that Menu, Plot Type, Box Plot.
And voila, we have a box plot.
And with it showing the outlier it is automatically doing the IQR test for us.
The Q3 minus Q1 times 1.5.
You get this number.
You add it to Q3, there is an upper boundary somewhere.
And you subtract from Q1 and get a lower boundary.
That IQR test is showing that this point out here is indeed an outlier like I intended
it to be.
If you don't want to make a modified box plot, you can hit Menu...
Plot Properties... and then you can Extend the Box Plot whiskers to all of the data.
So it is no longer Modified Box Plot.
You don't see the word Modified Box Plot in these menus.
Of course you don't see that in TI-83 and TI-84 either.
And you come back here and show the outliers again.
So that is entering data, and the 3 types of plots...
Dot Plot...
Box Plot... and Histogram.
Now we put in right skewed data.
Um..
Normal Probability plot we just studied recently.
You want a Normal Probability plot to look approximately linear if the data is indeed
approximately Normal.
Clearly ours is right skewed.
So let's make a Normal Probability Plot and see what that looks like.
So we had right skewed distribution.
Oh Oh.
It is off the screen.
Let's see here.
Zoom Data.
hmm...
That did not seem to change anything.
What is that about.
I actually expected that to change.
I am going to grab this axis over here.
You will do this by hitting the center of your touch pad, and grab it.
Scroll up until I see that rest of those values.
I am not exactly sure why it did not fit the window to that.
And again I am going to....
You will be using this pad.
You come up here to where this symbol comes up and you hold the center of your touch pad,
get the little closed fist, and then pull down.
Ok.
So do you see how that data is indeed not linear?
And you see the negative z scores, now... right now I have them set up to be on the
y axis... those negative z scores are all tightly packed.
The positive z scores start to become more and more spread out.
Those positive z scores, the data that was to the right of the mean becoming more spread
out.
That is what you have when you have a right skewed distribution.
I actually just keeping tabbing through all.. toggling through all these types of graphs.
I was going to try and go back and show you the histogram but I can't.
So let's just do menu, plot type, histogram, and there is that right skewed distribution
that you saw in the Normal Probability Plot that had the positive z scores more spread
out.
And of course now it is running off the screen again.
So there is how to do some univariate graphs on the TI-NSPIRE.
I am learning this as well.
Hopefully this blank screen is easier to see my cursor move around than the previous two
videos I just published.
If there is anything else you want to know how to do with this calculator please send
me a message.
If I do know how to do it I will post a video as well as continuing that through the year.
Thank you very much for watching.
Mr. Tarrou is out!