How Things Work - Doha Academy of Tertiary Studies

BOX 8.1. (cont.)
aveRaGes
analysis and Synthesis 147
“Does everyone have the average?” “Yes.” “This is not the only average.
There are three of them. The names of the three averages are mean,
median, and mode. Mean. Median. Mode.” She writes the three words
on the board. “The mean is what you just did. The second average is the
median. It has an ‘n’ at the end. To find the median, I want to show you
a trick Miss Jackson taught me.”
The numbers for Bazooka gum are still on the board. Grogan
crossed off the 10 at the left end of the row and the 19 at the right end.
She repeated that, left and right, until four measurements were crossed
off on each end, leaving only the middle two 11s not crossed off. She
says, “These 11s are the same, so the median is 11.” She had failed to put
the measurements in order of increasing value. She had indicated that
the median is the middle number in a row of unsequenced data.
She goes on to the mode. She identifies the mode as the number
that occurs most frequently in a set of data. “It’s whatever score comes
out the most. So for Bazooka, 11 comes up the most. What does median
mean? Median, Anna? What is the median? I just told you?” Grogan
goes on to tell about the median on a highway.
“What is the mode?” Angela says, “The number that shows up the
most . . . ” “Give me the mode of Bubble Yum.” “7.5 is the mode for
Bubble Yum.” “What is the mode for Extra, Carlos? There are three 4s,
only two 7s. What about Bubblicious?”
Listen, I am going to give you back the worksheet you had on Friday.
Tomorrow we are going to graph this information. Do not tear
it out of the notebook. What are you going to do, Monica?” “Math.”
“What is there to do for math?” “The worksheets.”
On Monday of the following week, I return to Audubon. In the
hallway, I notice a colorful and large new poster with the question,
“Which bubble gum makes the largest bubbles?” The answer displayed
is “Bubblicious.” About a dozen 8½ × 11 graphs are displayed, each
showing five monotonic traces, color coded as shown in its legend for
the five brands of gum. The graph Harry did is shown in Figure 8.3.
The 11 or so other graphed functions looked pretty much the same
as Harry’s, but not exactly. Harry and the other students had numbered
the ordinate from 1 to 34 and the abscissa from 1 to 35 but nothing
further to identify the two variables. For Harry’s, I presumed that the
(cont.)