Some college students collected data on the intensity of light at various depths in a lake. Here are their data:

Depth (meters) Light intenisty (lumens)
5 168.00
6 120.42
7 86.31
8 61.87
9 44.34
10 31.78
11 22.78

Take the natural logarithm (ln) of the light intensity measurements and calculate the least-squares regession equation for the transformed data to perform the inverse transformation to express light intensity as an exponential function of depth in the lake.