The following data represent the population of the United States for the years 1900-2010:

An ecologist is interested in finding an equation that describes the population of the United States over time.
(a) Determine the least-squares regression equation, treating year as the explanatory variable.
(b) A normal probability plot of the residuals indicates that the residuals are approximately normally distributed. Test whether a linear relation exists between year and population.
(c) Draw a scatter diagram, treating year as the explanatory variable.
(d) Plot the residuals against the explanatory variable, year.
(e) Does a linear model seem appropriate based on the scatter diagram and residual plot?
(f) What is the moral?

Transcribed Image Text:

Year, r Year, r Population, y Population, y 1900 76,212,168 1960 179,323,175 1910 92,228,496 1970 203,302,031 1920 106,021,537 1980 226,542,203 1930 123,202,624 1990 248,709,873 1940 132,164,569 2000 281,421,906 308,745,538 1950 151,325,798 2010