LigerBot Tracks FLL Donut Sales with Statistical Precision
December 8, 2018

The LigerBots sell lots of donuts made by team sponsor Dunkin’ at our FIRST LEGO League competitions. This tasty snack seems to hit the spot with our FLL teams, their families, and our maker fair visitors during the long and exciting day at Newton North High School. But we often run out of certain kinds of donuts, and end the day with other kinds left unsold.  Before this year’s FLL Newton Qualifier on November 17 team COO Jordan Y., who usually helps staff the concession stand, became curious about which donut types sell the fastest and which the slowest, and at what times of day. He figured that analyzing this information could help the team make good decisions at our future FLL tournaments about which kinds of donuts to buy for resale.

Clara, Jordan and Ben look over the stats on LigerBots donut purchases

During the Newton Qualifier Jordan took data. The LigerBots at the concession stand had a lively discussion, trying to predict when the most donuts would be sold. Although many team members believed that more donuts would be sold in the morning than in the late afternoon, it turned out that they sold at a fairly consistent pace throughout the day. Jordan found that although the donuts that sold out first were Oreo and Boston cream pie, the donut that sold at the fastest rate was plain glazed!

In this graph the slope of the trend line can be viewed as the rate at which each doughnut type was sold. Ironically, the doughnut type that had the most left over at the end of the day (chocolate frosting with tree sprinkles) sold at approximately the second fastest rate. We should buy fewer of the chocolate frosting donuts in the future even though the fast sales during the Qualifier gave the illusion that we would need more.
This graph shows all types of donuts in one line, demonstrating that donuts sell at a constant rate throughout the day, and not significantly faster in the morning.

While the results were incredibly interesting, Jordan plans to improve his data sampling at the FLL E. MA State Championship on Dec. 15 because of some flaws in gathering data at the Qualifier. There was a false fire alarm that caused everyone to have to exit the building for thirty minutes of our donut-selling time. Also, the number of donuts sold during certain time spans was approximated because of the rushed atmosphere at the concession stand, when selling food was prioritized over taking data.