Math 104
April 4, 2005
SPSS
Assignment 6 (due April 8)
Read Chapter 9 in the SPSS text: pp. 165-170,
180-182, 185, maybe peek at 187.
Turn in these problems:
Chapter
9 Concepts (pages 191-192): Problem 2
Chapter
9 Data Analysis (pages 192-194): Problems 5abcde, 9abc, 11ab, 15.
HINTS
AND SUGGESTIONS
Databases:
gssnet.sav (or gss.sav) for #5,
salary.sav for #9,
electric.sav
for #11,
country.sav
for #15.
Data Analysis:
In
all four exercises you need to make scatterplots as described on p.181 of the
SPSS Guide. In all cases you will select “Simple” in the “Scatterplot” dialog
box.
In several parts you are asked to make a
“sunflower plot” from a scatterplot. To make a sunflower plot from a
scatterplot, double-click on the scatterplot in order to open the Chart Editor
window. Under the “Chart” menu, select
“Options”. In the “Scatterplot Options” box (shown on p.186), click on “Show
sunflowers”. Then click on “OK”. Now close the Chart Editor. Your scatterplot
will now be a sunflower plot.
If you want to turn a sunflower plot back
into a scatterplot, then just repeat these same steps. When you click again on
“Show sunflowers”, your scatterplot will return.
In several parts you are asked to use “Point
Selection mode”. In the SPSS-Data Editor window each of the persons (or other
entities) is designated by an ID number in the far left column. Each point in
the scatterplot represents one (or possibly more) of these persons. You use
“Point Selection mode” to show you the person’s ID number.
To
turn on “Point Selection mode”, open the Chart editor for your scatterplot.
Click on the “Point Selection mode” button. (It is the button showing a little
square and an arrow pointing into it on the far left of the toolbar.) You should
enlarge the Chart editor window (by clicking the X button at upper right) so
that it takes up most of the computer screen (unless it is already enlarged).
Now
in the Chart Editor window click your pointer on each point whose ID number(s)
you wish to find. If a point represents more than just one person, then several
ID numbers will appear. Turn off the Point Selection mode before closing the
Chart Editor by clicking on the button again.
When you close the chart editor window, the
ID numbers of the selected points should appear on your scatterplot in the
Output window.
Sometimes
when you use Point Selection mode, you may have some trouble getting the
desired points “selected” because the points are bunched closely together. Just
make sure that the correct desired point is surrounded by a double-square when
you have clicked the square pointer over your point. That guarantees that the
ID number that appears is for the correct point. If the wrong point is
surrounded by the double-square, then just click the icon on it again to undo
the selection.
OPTIONAL: In problems #5d, #9b, and #15 below color is needed to distinguish
the points of the scatterplot, but the color will not print out. You may
instead change the shapes of the points so that points of different
colors are represented by different shapes. When you print out your
scatterplot, you will still be able to distinguish points of different colors
because they will have different shapes. Follow the directions on the next page
if you wish to make these changes to your scatterplots:
1) After you have your scatterplot with the
multicolored points, open the Chart Editor.
2) Now enlarge the Chart editor window so that
it takes up most of the computer screen (unless it is already enlarged) by
clicking the X button at upper right.
3) Under the “Format” menu, select “Marker”. The
“Marker” dialog box will open.
4) Under “Size”, click on “Small”.
5) Now click once on one of the small colored
squares shown on the lower right edge of the scatterplot that appears in the
Chart Editor window. When the small
square is clicked, go back to the Marker dialogue box and click on the symbol
(a marker) of your choice from the pictures shown. Now click on the
“Apply” button in the Markers dialogue box (not on the “Apply All” button). The small colored square on which
you clicked before will now be replaced in the scatterplot by your chosen
marker. Repeat this procedure for each of the small colored squares on the
lower right edge of the scatterplot, choosing differently shaped markers for
each different color. When you are done, close the “Marker” dialog box and then
close the chart editor. Now your scatterplot will have points distinguished by
shape as well as by color.
#5. Follow the special directions given here regarding
the printouts and the order of doing the various parts of this exercise.
When
you make the scatterplot, put the variable “husbeduc” on the horizontal axis (the X Axis) and put
the variable “wifeduc” on the vertical
axis (the Y Axis). Do not yet print
out the scatterplot. First proceed to parts (a) and (b).
#5a. You
may want to answer this question while at
the computer before you make changes to your scatterplot.
#5b. In the Chart Editor, under “Chart”, select
“Axis”. In the “Axis Selection” box click on “X scale” and then click on OK.
Then in the “X Scale Axis” box under the heading “Minimum”, change the
“Displayed” number to zero. Now click on “OK”. This will edit the plot so that
the negative years of education do not appear on the X-axis.
Now
repeat these same steps but for the Y-axis. The only difference is that this
time you click on “Y scale” in the “Axis Selection” box.
When you are done adjusting the Y-axis,
close the Chart Editor.
Print out your edited scatterplot before continuing to part (c), but do not close the output window containing
your scatterplot.
NOTE:
On this assignment and the next one (F) you may wish to use these same steps to
edit other scatterplots in order to remove unneeded negative values on the axes
(even if the directions do not ask you to do so).
#5c. Now make your sunflower plot from the
scatterplot in part (b). Print out
your sunflower plot, and then close the output window.
#5d. Begin
a new scatterplot for the two
variables exactly as in the beginning of this exercise, except that this time
enter the variable “life” in the “Set Markers by:” line as shown on p.181 of
the SPSS Guide. Then edit this
scatterplot exactly as you did in part (b) above to remove negative numbers
from the axes. Do not yet print out the
scatterplot until you have done part (e). You may wish to change the shapes
of your different colored points as explained previously. If you choose not to
change the shapes of the points, then answer the question in this problem while
you are at the computer.
#5e. Apply Point Selection mode to the scatterplot
from part (d). Now print out your
scatterplot with the ID numbers shown.
#9. Follow the special directions given here
regarding the printouts and the order of doing the various parts of this
exercise.
Make
the scatterplot by entering the variable “salbeg” on the horizontal axis (the X Axis), the variable “salnow” on the vertical axis (the Y Axis), and the
variable “sex” in the “Set Markers by:” line as shown on p.181 of the SPSS
Guide. You will now have the scatterplot as requested in part (b) of this
problem. You may wish to change the shapes of your different colored points as
explained previously. If you choose not to change the shapes of the points,
then answer the questions in parts (a) and (b) while you are at the computer. Print out your scatterplot before
continuing to part (c), but do not
close the output window containing your scatterplot.
#9c. Now
turn your scatterplot into a sunflower plot. Print out your sunflower plot.
#11. Print out your initial scatterplot before making the sunflower plot in
part (b).
#15. When
you make the scatterplot, put the variable “birthrat” on the horizontal axis (the X Axis), put the
variable “infmr” on the vertical axis
(the Y Axis), and put the variable “develop” in the “Set Markers by:” box.
YOU DO NOT NEED to draw the “Lowess.smooth”; just ignore that direction.
The
specific countries that are “different from the rest” that you are to identify
by Point Selection Mode are the three developed
countries having the highest infant
mortality rates among developed countries. These three should stand out of
the rest.
You
may wish to change the shapes of your different colored points as explained
previously. If you choose not to change the shapes of the points, then answer
the question in this problem while you are at
the computer. When you are done, print
out your scatterplot.
(end)