Real-Life Scenarios
Text Version

(Introduction music)
Image description: Marissa is in her kitchen heating liquids in pots on a stove. She is talking to Khalid on her cell phone. A split screen shows Marissa in her kitchen and Khalid at home in his living room sitting in a chair.

Marissa: Hi Khalid.  I have a problem.  I know my coffee cooling data should be exponential but the data is not showing a good fit for exponential regression.

Khalid: Did you account for the room temperature?

Marissa: What do you mean?  The room temperature is 60 degrees Fahrenheit.  Why does that matter?

Khalid: The exponential regression on the calculator expects that the data will approach 0.  In your data, the coffee should cool to room temperature.  So you will first need to subtract the room temperature from each data point before finding the regression equation.

Image description: As Khalid speaks, a graph appears with a descending curve that approaches zero. Then a table appears showing coffee cooling data, with a calculation for the number of degrees that the coffee sample is above the room temperature of 60 degrees Fahrenheit, 195 minus 60 equals 135.

Marissa: Wow, I didn’t know that.  I now know what to do with the data.  Thanks!