Stat 2000, Section 002, Homework Assignment 5 (Due 10/10/2001 11:59pm)
- 0) Reading: CyberStats Unit A-6 -- Describing Data Numerically
- 1) Please work on the following CyberStats exercises:
- Unit A-6 -- Describing Data Numerically, Exercises 1.1 - 1.7, 1.15 - 1.20
(1 Point each)
- 2) In class, we have seen many types of static statistical
graphics such as histograms, pie charts, or even micromaps.
Since these graphics are printed on paper, there is obviously
no possible interaction with these graphics. However, a medium such as the
World Wide Web allows to interactively manipulate statistical
graphics. It is to be expected that in the near future more
and more statistical data, e.g., from Government agencies,
can be interactively accessed and manipulated on the Web.
One tool that allows such an interaction with statistical
graphics on the Web is the Graphics Production Library (GPL) at
http://www.monumental.com/dan_rope/gpl.
(a) Describe in two or three sentences what the 4 `Sample Applets'
(Barley, CPI, Unemployment, and TRI Release) are about.
To make use of the full potential of these interactive graphics,
you should also look at the Overview page at
http://www.monumental.com/dan_rope/gpl/overview.html
and apply these features to some of the interactive graphics.
(4 points)
Depending on the time of the day, type of computer, and connection
to the Internet (modem or directly at USU), it can take a few
minutes before something happens on your computer screen. If you
cannot bring anything to show up on your screen, see me during
my office hours and we can jointly look at these applets.
(b) Now look at the Barley data at
http://www.monumental.com/dan_rope/gpl/barley.html
again.
Zoom the data such that all regions are visible at the
same time and compare the two years 1931 and 1932 (this can be done
most easily if you grab one of the data columns with the mouse
and move it into the other data column - if this does not
work with your Web browser, look at the data very carefully...).
Isn't there something strange in the data? Explain! (2 points)
If you are interested in more details regarding
the GPL, there is an article by Carr, Valliant and Rope
about the GPL published in Vol. 7, No. 2, pages 19-26, in the
Statistical Computing and Statistical Graphics Newsletter
which is accessible at
http://cm.bell-labs.com/cm/ms/who/cocteau/newsletter/index.html.
- 3) The following questions are based on the data for the
``Weider Empire'' from USA Today (May 15, 1998) reprinted below.
(6 Points)
- Determine the mean magazine circulation
for the ``Weider'' empire.
- Determine the median magazine circulation for the ``Weider'' empire.
- Assume you are the press speaker of the ``Smith'' magazine group that also has
10 magazines with a mean circulation of 310,000 and a median circulation of 300,000.
Which number(s) would you report when comparing your group with the ``Weider'' empire.
Explain.
- Calculate the range of the magazine circulation for the ``Weider'' empire.
- Construct a stem-and-leaf display of the magazine circulation.
- Are you happy with the data provided by USA Today? Isn't some
important information missing?
- Do you think that the 1.1 million circulation for ``Shape'' is the
absolute truth? Think of possible manipulations (hint: ``TV Guide'' published
4 collector's covers of Seinfeld in their May 9-15, 1998, issue - how might this
effect the circulation?).
- Assume the
``Weider'' group only possesses these 10 magazines. Calculate
the variance and make a clear statement whether you are calculating a population
or a sample variance.