Time: Approximately 60 minutesMaterials:
(Optional) Statistics utility program or graphing calculator.
Prerequisites: This activity is designed for students
who have a good understanding of linear functions, some knowledge
of quadratic functions, and what is meant by a polynomial
function. They should also be familiar with graphical
representations of these functions.
Implementation: This RWLO can be used either in the
classroom to demonstrate goodness of fit of a model or provided as
an activity / homework assignment for students. Students can work individually or in small
groups but it is recommended that each student answer the
questions individually.
Steps:
 Read and/or distribute
Background Information for the Global Sun  Temperature
Project.
 Review and/or distribute
Part A:
Latitude vs. Daylight. You can review this part together
with students in class or assign it as an inclass or
outofclass activity. If assigned as an
outofclass activity, there should be a followup
class discussion that includes why a certain model was chosen,
whether another function might also work, what restrictions are
placed on the domain and range by the problem situation, and
whether the model could be used to predict future values.
Although no one answer is correct, some answers may be better
than others.
 Review and/or distribute
Part B:
Latitude vs. Temperature. Students should complete this
activity as an independent assignment.

Optional Activity:
In lieu of viewing the data plots provided in
this RWLO, students can download
archived data from other runs of the Global Sun  Temperature
project and create their own models using a statistical utility
program. Note that all of the models and charts created in this RWLO
were done using EXCEL but other programs may be more appropriate. To
create the residual plots, insert two additional columns into the
spreadsheet; one for predicted values (y) using the equation
for each model (x=latitude) and the other column for the
residual calculation (residual = observed  predicted). You
can then create plots of the residuals for each value of latitude.