The U.S. Population The following data represent the population of the United States for

Chapter 14, Problem 22

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The U.S. Population The following data represent the population of the United States for the years 19002010: Year, x Population, y Year, x 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 1950 151,325,798 2010 308,745,538 Source: U.S. Census Bureau 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? (Hint: See Section 4.3.) (f) What is the moral?