Uni vs. Bi-variate data
Clearing data
20
T
T
H
H
E
E
S
S
T
T
A
A
T
T
I
I
S
S
T
T
I
I
C
C
S
S
A
A
P
P
L
L
E
E
T
T
-
-
B
B
I
I
V
V
A
A
R
R
I
I
A
A
T
T
E
E
D
D
A
A
T
T
A
A
As mentioned in the Univariate section, one of the major strengths of the hp 39gs & hp 40gs is the tools they
provide for dealing with statistical data. Unlike the others, the Statistics aplet begins in the
NUM
view which
offers easy input and editing of values, while the
SYMB
view is reserved for specifying which columns contain
data and which ones frequencies, as well as for indicating pairing of columns for bivariate data.
The hp 39gs & hp 40gs treat univariate and bivariate data quite differently and those differences are reflected
in the
SYMB
and
PLOT
views. Because of this the Statistics chapter has been split into two.
The previous section dealt with univariate data and we are now going to
look at bivariate (paired) data. On the screen in the
NUM
view of the
Statistics aplet you will see a key labeled as either
or
.
Pressing the key under this label changes from univariate (
) to
bivariate (
) and back. Make sure the key is showing
before proceeding.
x
i
y
i
1 5
3 10
8 18
5 13
7 16
3 8
6 15
2 8
7 18
9 22
8 17
5 15
7 14
6 18
8 20
5 12
2 8
0 4
7 17
8 19
If your
NUM
view already has some data in it,
press
SHIFT CLEAR
(above
DEL
) and choose
All columns
.
The
DEL
key is used to delete individual pieces of
data, rather than whole columns. One must be
careful when doing this for bivariate data. If your
data pairs were in column 1 (
C1
) and column 2
(
C2
) then deleting a single piece of data from
C1
without deleting its paired element in
C2
would
destroy the relationship between the two columns.
In this chapter we will use the set of data left to
show the use of the bivariate features of Statistics.
We will obtain all the usual statistics on it, and
draw a scatter graph.
123