Course Guide - USAID Teacher Education Project

e) Once youngsters know that there can be more than one mode, they may see agraph such as the one below and become confused when they see that there are valueswith the same height (as in the intervals labeled 20.0 and 25.0, and 30.0 and 45.0).They may assume these are multiple modes, not remembering that the mode needs tobe the "most frequent" in the data set (50.0), not just the "height of the bars thatappear most frequently."Loretta, what does “DEPTH” mean on the above bar graph?f) If a data set contains an odd number of entries, it is relatively easy to find themedian. Consider this data set: 1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 26.Youngsters can use the "counting from both ends" strategy to arrive at the correctmedian: 3.Other youngsters, however, may add the numbers in the data set and divide that sumby 2. (When the sum for the above 11 entries (55) is divided by 2, the result (27.5) isincorrect.)g) If a data set contains an even number of entries, things become more complicated.There is no "middle value" in the data set when "counting from the ends." Instead,the median is somewhere between the middle two values.In the following data set (3, 7, 16, 25, 32, 39), the median is “somewhere” between 16and 25. The median is found by adding 16 and 25, then dividing the sum by 2,resulting in 20.5, which not a number in the data set, nor an integer.Youngsters need help knowing how to interpret their accurate calculations, especiallyif an integer would be the only sensible solution to a real-world data situation. Forexample: one family has 3 children; another family has 2. The median number ofchildren per family is 2.5—surely not a realistic result, but a valid mathematical one.