When the ordered stem and leaf plots for grouping by tens and grouping by fives are placed next to each other, you can see the connections between the two as well as some different patterns in the variation.

Each stem of the first stem and leaf plot corresponds to two stems in the second: one that represents the lower five digits in the leaves and one that represents the upper five. Increasing the number of stems (e.g., five units per stem rather than 10) allows you to see smaller degrees of variation between stems, but each stem will generally have fewer leaves. You must find the best compromise between stems that are too wide to differentiate between data and stems that are too narrow to see trends in the overall data.

You can choose different-sized groupings for the stem and leaf plots for different data sets (e.g., one can be grouped by fives and one can be grouped by 100s, if those are the groupings that will work best). In general, try to use no fewer than five and no more than 15 stems when constructing a stem and leaf plot.

Problem A8

Based on the stem and leaf plot grouped by fives, give two descriptive statements that provide an answer to the question "How well do people judge when a minute has elapsed?" Your answers should take into account the variation in the data.

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