Prolog for a Winter Day -- TI-92

You can work through this module either using your own data or using the data included in these files.

• Using your own data: If you are using your own data then you have loaded it directly into the TI-92 from the TI-CBL. You have probably collected four lists of data.
  • Time data in the list l1. This data will be used exactly as is.

  • Temperature readings from the probe in the air. This data is only used to check that the air temperature (room temperature) stayed relatively constant during the experiment. If it did not then you will need to run the experiment again trying to keep the air temperature constant.

  • Temperature readings from the probe in the water in calm air. To analyze this data you will need to move it to the list l2.

  • Temperature readings from the probe in the water under the fan. To analyze this data you will need to move it to the list l2.

• If you use the data included here then you will either need to type it into your TI-92 or, if you have the TI-Graph Link program and cable and your browser is configured to use this program then you can download the data to your TI-92 by clicking in the TI-Graph Link Program icon below and downloading the program cooldata to the TI-92 in the usual way. After you've downloaded the program, run it by typing cooldata() in the home screen and pressing ENTER. The time readings will be placed in the list L1 and the temperature readings will be placed in the list L2.
  

  There have been numerous problems downloading programs for TI graphing calculators using the method above. If that method works, it is very clean. Sometimes, however, it doesn't work. In that case we can fall back on an older method, uuencoding, that is less user-friendly but more reliable. Click here for more information about this method. Then click here for a uuencoded (text file).

  If your only choice is typing in the data then you should place the temperature readings in the list L2. The time readings can be placed in the list L1 with the line

  

Whatever data you use the program fitdata will fit a curve of the form

There have been numerous problems downloading programs for TI graphing calculators using the method above. If that method works, it is very clean. Sometimes, however, it doesn't work. In that case we can fall back on an older method, uuencoding, that is less user-friendly but more reliable. Click here for more information about this method. Then click here for a uuencoded (text file).

To run the program fitdata type fitdata() in the home screen and press ENTER. The program will ask for the values of n and p as described in your browser window. After fitdata has computed a model you can compare the model and the original data using the TI-92 table and graph features in the usual way. Make sure that the graphics mode is set to SEQUENCE. You may want to look at the help files for graphing a sequence or making a table for a sequence.

The screen at the right shows how the Y= screen should be set up for both the table and the graph.
The screen at the right shows how the window screen should be set up to graph the original data and the model.
The screen at the right shows the graph for the data given here and the model obtained using n = 20 and p = 20. Notice the original data is shown by dots and the model with a solid line.
The screen at the right shows how the the TblSet screen should be set up to produce a table showing the original data and the model.
The screen at the right shows the same data and model as the graph above but in tabular form.