=+60. Life expectancy. Life insurance rates are based on life expectancy values compiled for large demographic groups.

But with improvements in medical care and nutrition, life expectancies have been changing. Here is a table from the National Vital Statistics Report that gives the Life Expectancy for white males in the United States every decade during the last century (1 = 1900 to 1910, 2 = 1911 to 1920, etc.). Consider a linear model to predict future increases in life expectancy. Would re-expressing either variable make a better model?

Decade 1 2 3 4 5 6 7 8 9 10 Life exp. 48.6 54.4 59.7 62.1 66.5 67.4 68.0 70.7 72.7 74.9