The water level, w, in feet, of a river after a rainstorm is a function of the time, t, in hours, since the storm began. The table below shows the water level readings collected at different times.

Hours Since Storm Began (t) Water Level (w) 1
1 18.7
1.5 19.1
2 19.5

Write a linear function that models the data in the table. w(t)=