Annual estimates of the population in the age group 65+ in a mid-sized city from 1999 (t = 1) onward are shown in the time series graph below. a. Identify the dominant time series component(s) in the data.
b. Below are the results from fitting a linear trend model to the data. Use this model to estimate the 65+ population in this city for 2008 (t = 10). c. Below are the results from fitting a quadratic trend model to the data. Use this model to estimate the 65+ population in this city for 2008 (t = 10). d. The actual population estimate for 2008 is 157,218. Which model does better? Why?

Question

Annual estimates of the population in the age group 65+ in a mid-sized city from 1999 (t = 1) onward are shown in the time series graph below.  a. Identify the dominant time series component(s) in the data.
b. Below are the results from fitting a linear trend model to the data. Use this model to estimate the 65+ population in this city for 2008 (t = 10).  c. Below are the results from fitting a quadratic trend model to the data. Use this model to estimate the 65+ population in this city for 2008 (t = 10).  d. The actual population estimate for 2008 is 157,218. Which model does better? Why?

Quizplus · Accepted Answer

The Answer is a. Trend
b. 153,713
c. 156,197
d. The quadratic trend model does better. As can be seen from the time series graph, the trend is not linear.

Annual Estimates of the Population in the Age Group 65