NAME:	Televisions, Physicians, and Life Expectancy
TYPE:	Sample
SIZE:	40 observations, 6 variables

DESCRIPTIVE ABSTRACT:
For each of the forty largest countries in the world (according to 1990
population figures), data are given for the country's life expectancy
at birth, number of people per television set, and number of people per
physician.

SOURCE:
_The World Almanac and Book of Facts 1993_ (1993), New York:  Pharos
Books.

VARIABLE DESCRIPTIONS:
Columns
 1 - 15  Country
23 - 26  Life expectancy
29 - 33  People per television
36 - 40  People per physician
43 - 44  Female life expectancy
47 - 48  Male life expectancy

Values are aligned and delimited by blanks.
Missing values are denoted with *.

SPECIAL NOTES:
A country's life expectancy was calculated by averaging the life
expectancies for females and males.  In most cases the almanac listed
the ratios of people per television and people per physician directly.
In the few cases for which the almanac listed the raw numbers, the
ratios were calculated from the population information.  The only
missing values are people per television in Tanzania and Zaire.

STORY BEHIND THE DATA:
These data were gathered from _The World Almanac and Book of Facts
1993_ to enable students to explore properties of association,
correlation, and prediction in a context that is very easy to
understand.

Additional information about these data can be found in the "Datasets
and Stories" article "Televisions, Physicians, and Life Expectancy" in
the _Journal of Statistics Education_ (Rossman 1994).

PEDAGOGICAL NOTES:
These data provide a useful context for students to discover the
fundamental principle that correlation does not imply causation.  They
also give students an opportunity to explore data transformations and
to consider whether a causal connection is necessary for one variable
to be a useful predictor of another.  People per television is
negatively associated with life expectancy, and the log transformation
makes it a slightly better predictor of life expectancy than people per
physician.

SUBMITTED BY:
Allan J. Rossman
Dickinson College
Department of Mathematics and Computer Science
P.O. Box 1773
Carlisle, PA  17013
rossman@dickinson.edu