The logistic population growth model is described by an equation of the form
P(t) = PL/(1 − ce−kt) ,
Where PL, c, and k > 0 are constants, and P(t) is the population at time t. PL represents the limiting value of the population since limt→∞ P(t) = PL. Use the census data for the years 1950, 1960, and 1970 listed in the table on page 105 to determine the constants PL, c, and k for a logistic growth model. Use the logistic model to predict the population of the United States in 1980 and in 2010, assuming t = 0 at 1950. Compare the 1980 prediction to the actual value.