Several Years Ago, the Wild Rabbits of Australia Were Seriously $r$

Short Answer

Several years ago, the wild rabbits of Australia were seriously threatened by a virus that was accidentally released into their population. Suppose that the following table gives the number $r$ of rabbits (in millions) remaining $t$ months after the release of the virus.

Use a calculator program to find the slope of the linear regression line for this data. Round to 3 decimal places.