Casio FX-9750GII - SOFTWARE VERSION 2-00 User manual

2010 Back-To-School
Statistics SneakPeek
Featuring the Casio fx-9750GII

Statistics? Some people aren’t sure what it is. The best thing about statistics is that it’s about real life. It’s
based on actual information (at least usually) we call data. Instead of a lot of details now, let’s get to know
what data means by examples. Ready?
∂Press the Obutton to turn your calculator on.
∑When your calculator first gets powered on out of the
package, it should display the ain enu. If you
have already used your calculator, just press
the pkey.
∏We’re going to do statistics. ake a wild guess –
which of these menu items do we want? Brilliant!
It’s STAT. There are two ways to tell the calculator to
go there. One is to use the arrow keypad (the oval-
shaped thing that says REPLAY in the middle)
tomove right, $and highlight the STAT icon. Once it’s highlighted, press l.
The other choice is to simply press 2.
πLists! Everybody’s got them – song lists, shopping
lists, to-do lists, wish lists, well you know what you
have. This calculator feature is about lists, too. In
fact, we’ll call it the list editor. Suppose you asked
everyone in your math class for his/her type of pet and
“the survey said”:
Put the five values in List1. Press lafter each value to move to the next position in the list.
∫Notice those icons along the bottom of your screen? Those are called soft keys. Let’s check out the
first one, GRPH. No, it’s not an animal with a long neck. Just imagine “I’d like to buy a vowel,
please. Is there an A?” There is! It’s really Graph, but the whole word didn’t fit. Press q.
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2010 Back-To-School - Statistics SneakPeek
Featuring the Casio fx-9750GII
Type How many
None 2
Bird 3
Cat 8
Dog 10
Fish 7

œGA E, SET, and ATCH! Well, not quite, but we
are ready for SET. It’s more like set it up. This is
where we tell the calculator about the graph we want
to make. Press u.
ºPie! mmmm! aybe Apple or French silk?
Actually we’re going to make a pie chart. The top
line probably reads StatGraph1. If it doesn’t, just
press qto change it. Now press Nto select
Graph Type. Press rto select the Pie chart.
Also check that List1 and % are selected as shown.
Press dand qto see the chart.
ΩNow try to change the graph to a Bar chart.
Press u(>)to find the Bar graph option.
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2010 Back-To-School - Statistics SneakPeek
Featuring the Casio fx-9750GII

The example we have just done uses categorical data. The choices such as dog and cat are categories, and
the values we used are counts, because we counted how many people had that type of pet. Now we are
going to use quantitative data, where we get values that are more like measurements than counts. Suppose
we record the height for you and eight of your friends and we get these nine values:
63, 64, 64, 65, 66, 67, 68, 68, 70
∂Press dto return to the List editor and put these
values in List1.
∑Use SET to make a new type of graph. Use Nto go
to Graph Type. This time we don’t see the type we
want. Notice the arrow above F6? That means there
are more choices. Press u.
∏“The dangerous, poisonous snake Hist at them!”
Well, not quite. Hist stands for histogram. It’s like a
bar chart, but a better choice for quantitative data.
ove down to Graph Type and press q. Check that
the next row shows List1. Press dand q.
πA window opens up to help us make a nice graph.
Use a number smaller than those in our list, like 60,
for Start. Use 1 for Width. Width means the width of
each rectangle in our histogram. Our height values
are very close to one another so 1 is a good choice.
Press lto see the graph.
∫Box and whisker? That’s a joke right? Actually, no.
It is the name that statisticians use for another kind of
plot, although, sometimes it is called a boxplot. If
you are going to make these, your teacher will ex-
plain the details. For now, for a little extra practice,
change your graph by using the Graph Type Box.
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2010 Back-To-School - Statistics SneakPeek
Featuring the Casio fx-9750GII

œLet’s do one more thing with these data. Press da
couple of times to return to the List Editor, and the
GRPH soft key. Look next to it. There’s CALC.
Well, it is a calculator, right? It should be able to cal-
culate. We actually get a lot of calculating. Press w
and then qfor 1Var (because we have only one
variable, the heights). We get a lot of information
about our data, like the mean (or average). Press N
to scroll down and see even more, like the median and
the maximum values.
Sometimes we work with paired data. As the name suggests we have two variables that we believe are
associated. For example, you may have heard something like this: if you extend your arms straight out
parallel to the floor, and measure fingertip to fingertip, it is about the same as your height. Suppose we did
this with you and your eight friends. Now each person has a pair of numbers, height and arm span.
We can check out this theory. Let’s suppose the measurements are:
65, 64, 63, 66, 64, 68, 70, 67, 70
It would be important to know that the numbers are
matched up, that is the first number in the list is for the
same person as the first number in the height list.
∂Return to the list editor and put these values in List2.
Press q(GRPH) and then uto set up a graph.
∑Scat! Trying to chase that cat away? The Cat in the
Hat, maybe? Fox in Socks? OK, probably not. Scat
stands for scatterplot and we make one to see a pic-
ture of our pairs. It’s just like plotting points in Alge-
bra class. Change the Graph Type. Also make sure
List1 and List2 are selected. You can even choose the
size of your points with ark Type.
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2010 Back-To-School - Statistics SneakPeek
Featuring the Casio fx-9750GII

∏Press dand q(GPH1) and you have your plot.
The calculator created a good window to see these
points. Pretty cool!
πSometimes we try to get a model. No, not that kind
of model! In statistics, a model means an equation
that helps to see how the variables are associated.
The simplest type of model is linear. Now, our data
isn’t perfectly linear; we see that the points are not in
a perfect line. For some people arm span does equal
height, but for others it is a little more or less.
The model would describe the overall association
for the whole group, and show us a linear equation
like y = ax + b. I know, you’re used to m for slope.
In statistics, coefficients are almost always a, b, c, etc.
Let’s try it! Press da couple of times to return to
the List Editor, and the GRPH and the CALC soft
keys. Press w(CALC).
∫We used 1Var before, but this time we want REG.
Reggae! Let’s get some music going! Everybody
dance! Well…no. REG stands for regression, and it’s
a fancy word for “let’s find the best model.” Details
about “best” would be given in a statistics class.
For now…believe! Press e(REG). Now we see a
whole lot of choices about the type of model. The
one with the plain X is our linear model, so press q.
We get two choices, go with qagain. We see the
slope and y-intercept for our model, along with some
other information.
œSee that COPY soft key on the right? It saves a lot of
work. It will copy our equation for us, so we don’t
have to write it down and type it all in. Press u. Now
we see the function editor; you probably used this
editor a lot in algebra class. You get to select which
place to copy the equation. Y1 is the usual choice, so
press l. Press d several times to return to the List
Editor and the GRPH soft key. Press qtwice to see
the scatterplot. Press w for DefG, define graph.
Now you can see that the calculator really did
copy your equation.
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2010 Back-To-School - Statistics SneakPeek
Featuring the Casio fx-9750GII

ºDRAW! It's not really a gunfight on some video
game. It’s, well, draw, that’s draw the graph. The
line is shown with the scatterplot.
ΩPress Lqto Trace on the graph. At first, you
are on the scatterplot, and you see the pairs. If you
press N, then you are on the line.
This is an introduction to some of the things you can do
with this exciting calculator when you are learning about
statistics. There are many more features to explore,
especially if you take a statistics class in high school.
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2010 Back-To-School - Statistics SneakPeek
Featuring the Casio fx-9750GII