8.36 Life insurance policies in force. The next table represents all life insurance policies (in millions) in force on the lives of U.S. residents for the years 1980 through 2006.(a) Fit the simple linear regression model, E(Yt ) = ?0 + ?1t , to the data for the years 1980 to 2006 (t = 1, 2, . . . , 27). Interpret the results.b) Find and plot the regression residuals against t. Does the plot suggest the presence of autocorrelation? Explain.(c) Conduct the Durbin-Watson test (at ? = .05) to test formally for the presence of positivelyautocorrelated regression errors.(d) Comment on the validity of the inference concerning model adequacy in light of the resultof part b.

LIFEINS YEAR NO. OF POLICIES YEAR NO. OF POLICIES (in millions) (in millions) 1980 402 1994 366 1981 400 1995 370 1982 390 1996 355 1983 387 1997 351 1984 385 1998 358 1985 386 1999 367 1986 391 2000 369 1987 395 2001 377 1988 391 2002 375 1989 394 2003 379 1990 389 2004 373 1991 375 2005 373 1992 366 2006 375 1993 363 Source: U.S. Bureau of the Census. Statistical Abstract of the United States, 2009