The population of Manhattan Island in New York City between 1890 to 1970
represents the population and x represents the number of years since 1890.
a. According to the data at the right, how valid is the model?
b. Use the model to predict the population in 1980.
c. According to this model, what happens between 1970 and 1980?
d. Do you think this model is valid for any time? Explain.