Question

A quadratic model was applied to motor vehicle toxic emissions data collected between1984 and 1999 in Mexico City. The following equation was used to predict the number (y) of motor vehicles without catalytic converters in the Mexico City fleet for a given year (x):

yˆ = -2287000 − 321.67x + 0.794x^2.

1) Explain why -2287000 has no practical meaning.

2) Researchers use the model to estimate that just after the year 2021 the fleet of cars WITH catalytic converters will completely disappear. Comment on their prediction.

Answer 1