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Copyright 1994 Star Tribune
July 1, 1994, Metro Edition
SECTION: News; Pg. 3B
LENGTH: 771 words
HEADLINE: Completing math literacy;
Teachers attend 'U' seminar on probability and statistics
BYLINE: Jim Dawson; Staff Writer
For the past week 35 junior and senior high school math teachers from
Minnesota sat in a room with several of the top mathematicians in the country
trying to learn and decipher the tricky mathematics of chance.
It was intense, dense work, with statistics, correlations, probability and a
thicket of other concepts challenging the brains of the teachers of Minnesota's
youth. The gathering was the annual mathematics seminar for teachers sponsored
by the University of Minnesota's Geometry Center. Here is how one morning's
"How do you deal with 12 things?" asked John Weisser, of Bloomington
Jefferson High School, as he was presented with a rating problem.
"I don't know," answered Samuel Boyson, of Breckenridge High School.
"Maybe the test will be double-blind," offered Michelle Appelgren, of St.
Louis Park High School.
Weisser later pulled out a theory to solve the problem from a discreet
mathematics course he had once taken.
Rocket science? No. Quantum physics? Hardly.
The three were in search of the best chocolate chip cookie.
And they and their colleagues found it: the Pepperidge Farm soft baked
chocolate chip cookie beat out 11 other contenders. The worst was the Famous
The object wasn't just to find the best and worst in terms of taste, but to
cross-rate the cookies based on cost, and in the end, when the scatter graphs
were computerized and displayed, the rule generally held: With an exception or
two, more expensive chocolate chip cookies taste better than less expensive
The object of the weeklong seminar was, of course, much more than ranking
cookies. It was to steep teachers in an area of mathematics that is part of
everyday life, yet nearly ignored in high school textbooks.
"Probability and statistics is an area of mathematics used by everyone every
day, and it gets short shrift," Appelgren said.
"It's not in the textbooks, it's not in our training, yet it's part of
mathematics literacy," said Naomi Baer, a teacher at Central High School in St.
With Dartmouth College mathematics Prof. J. Laurie Snell leading the way,
teachers looked at everything from how DNA statistics are interpreted in the
courts to the reliability of political polls.
"Today we're asking them what does margin of error mean," Snell said, as he
handed out articles from the New York Times and the Star Tribune. A Star
Tribune Minnesota Poll article said, "One can be 95 percent confident that error
due to sampling will be no more than plus or minus 4.4 percentage points."
Snell then pointed to the New York Times poll, which explained the margin of
error this way: "In theory, in 19 out of 20 cases the results based on such
samples will differ by no more than 3 percentage points in either direction."
Both polls say about the same thing in different ways, he said. What it comes
down to is about 5 percent of the time, due to chance and bad luck, polls get
numbers that don't reflect reality, he said.
The object of the polling studies was to show the teachers how polls are
done, why they usually are so accurate at predicting election and other results
when only a small sample is taken, and why, occasionally, they are wrong. It has
a great deal to do with mathematics, with figuring means and standard
deviations, with paying attention to the numbers.
The goal of the course, the teachers were told, was to "make you better able
to come to your own conclusions about news stories involving chance issues."
The teachers are expected to take what they learn back to their classrooms. While
the math is difficult, the real-world nature of it can so involve the students
in learning - be it baseball statistics or chocolate chip cookies - that the
teaching becomes easier. The teachers were the best example of that. Once they
started on their quest for the best cookie, emotions ran high and the
instructors could almost step aside. "We didn't think it was reasonable for
anybody to sample 12 cookies," a member of one team said. "So we decided to
divide them into groups of three."
"He's stratifying it," someone noted, as another team decided that 12
cookies were too many to rate. "So we're going to eliminate four by appearance,"
A woman on another team objected, noting that she had refused to eat pecan
pie in her youth because she didn't like the look of it, but then discovered it
was good. "Some ugly cookies taste good," she said. And so went the advanced
course on the difficult subject of probabilities and statistics.