A Formula for Mountain Day? It All Adds Up to Fun

This year’s Mountain Day celebration was all about fun—both on and off campus.

The arrival of the longtime Smith tradition (established in 1877) also raised a question: Is there any way to predict when the president will call the surprise break from daytime classes and appointments?

Consultation with experts in the Department of Mathematics and Statistics resulted in the following list of criteria for predicting Mountain Day:

1. After the leaves have started to turn;
2. Before Fall Break;
3. Not on a Friday, lest students disappear for an entire weekend;
4. After Quad Riot;
5. Before the start of hunting season (note that state laws forbid both bear and deer hunting on Mountain Day this year, though archery was allowed);
6. At the early morning whim of the president.

Ruth Haas, Achilles Professor of Mathematics and Statistics and professor of engineering, suggested (with a smile) that a workable formula for determining Mountain Day “is to use the same strategy one would use for a multiple choice test when you are not sure of the answer.”

That means proceeding by the process of elimination, said Haas, who is co-director of the Center for Women in Mathematics.

Ignoring the criterion “whim,” applying each of the others on the list significantly reduces the number of possible dates for Mountain Day.

“When you cross off all the days that violate the rules, you’ll be left with only a few possible choices,” Haas explained.

“To decide between the remaining criteria, Haas offers a 7th rule to consider: ‘the first of the remaining days on which the weather is predicted to be nice.'”

So, how close did the campus mathematicians come to correctly predicting that September 29 would be this year’s Mountain Day?

That date “was certainly on my list,” Haas said.

“I didn’t predict it, but I sure hoped for it,” said Marjorie Senechal, Louise Wolff Kahn Professor Emerita in Math and the History of Science. “I had overscheduled the day.”

Sarah Devine ’15 enjoys a Mountain Day outing to an apple orchard. Photo by Shannon Johnson ’15.