Using the data below, identify the IQR (interquartile range).
26, 17, 21, 23, 19, 28, 17, 20, 29

The population of a small rural town in the year 2006 was 2,459. the population can be modeled by the function below, where f(x residents and t is the number of years elapsed since 2006. f(t) = 2,459(0.92)