AP Biology students put Mars, Incorporated to the test this week using colorful M&M’s and a statistical formula to determine whether the company’s published color ratios hold up in real life.
The Chi Square lab, led by AP Biology teacher Miranda Katz, challenged students to act as quality control scientists by comparing their observed candy color counts to the percentages reported by the company. The goal was to determine whether any differences were due to random chance or something statistically significant, giving students hands-on experience applying mathematical analysis to biological concepts.
“Chi Square is a statistical test,” Katz said. “[It] helps students determine whether the difference between what they observed in an experiment and what they expected to see is due to chance or due to something biologically meaningful.”
Rather than simply reading about genetics and probability, students calculated expected values, organized class data into tables and used the Chi Square formula to decide whether to accept or reject their hypothesis.
“Because science is something you do, not something you just read about,” Katz said. “When students physically collect or analyze data and then apply statistics to it, they build deeper conceptual understanding. It also allows students to practice real biological research, collecting data and using tools to interpret it.”
Students said the lab helped make a challenging concept more approachable.
“I learned how to do a chi-square table, which helps us see if our hypothesis of what we expected is right,” Tuscany Morthole said. “It also shows how this concept can apply to everyday life.”
In addition to crunching numbers, students were asked to write a letter to Mars explaining their findings, a creative twist that made the assignment more engaging.
“I like to perform in labs because it lets us get hands on, and learn in a different way,” Morthole said. “Especially when the concept we are learning is difficult to understand. It helps me learn how to do it in a different way.”
