M-Step Week, PT: Rush or Pass?

Given actual data from the NFL, regular season, 2013, students had to determine what is the best strategy, rushing or passing?

Due to M-Step testing, I only met with my 7th grade students three times this week.  All three class periods were spent on the PT: "Rush or Pass"

• Students started in groups of two, one graphing Rushing Yards vs. Points Earned and the other graphing Passing Yards vs. Points Earned.
• On day two, teams of two were combined to become teams of four.  I asked them to compare results and come up with a recommendation for the best strategy as if they were hired by a football team.  They would prepare a presentation for the class, backing up their strategy with mathematical evidence.

During work on the task, I noticed:

• No students asked for help determining the scale used on either axis.  However, students did comment on each other's, with things such as "Whoa, your scale is too big, your points look all bunched up." 
  
• Students who do not understand football, struggled at first, but realized it was not important.
• Many student struggled with how best to find slope.  Note: make sure students are using points on their line of best fit and not just from the table.
• Students used terms such as "outlier," "scale," "slope," and "rate of change" during their discussions.

During presentations:

• Most teams justified their solution by comparing the two slopes.  For example: " Our slope for rushing was steeper, so you get more points per yards than for passing." 
• Some teams mentioned one data set having a stronger linear correlation than the other.
• Some teams used their equations for lines of best fit, substituted the same value for x into both and found which resulted in more points.
• Students in the audience often asked to see the graphs as evidence.
• Students made remarks about the importance of scale.
• There was a lot of discussion and debate whether the y-intercept had to be zero, or not.

Working in teams of two to start: