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2.2 Graphs and Tables for Quantitative Data Objectives: By the end of this section, I will be able to… 3) Construct and interpret stem-and-leaf displays and dotplots.

Section 2.2 Part 2 Stem and Leaf Displays and Dotplots

Stem-and-Leaf Plots: A quick way to organize pieces of data. Each data point is shown.

Rules for a Stem and Leaf 1) Put Data in Order FIRST 2) Choose your “stem” 3) Organize your leaves with the appropriate stem.

SORT DATA First thing we want to do is plug the data into our calculators (STAT – EDIT – LIST1) First thing we want to do is plug the data into our calculators (STAT – EDIT – LIST1) Then Sort your data (STAT – SORTA() – 2 nd 1 – ENTER) Then Sort your data (STAT – SORTA() – 2 nd 1 – ENTER)

The “stems” will be the digits in the tens place. Place them vertically from smallest to largest

Working left to right in the data set, places the “leaves” (the digits in the ones place) in the corresponding row in ORDER

Stems Leaves 7 1 means KEY or LEGEND of the Stem and Leaf Plot

If the stem and leaf plot is turned sideways, a histogram is created s 80s 90s 100s 70s Intervals

How much money did you spend on shoes last year (estimate)? Make a stem and leaf plot displaying our results

means 2.8

DOT PLOTS Simple graph to make Simple graph to make Shows relative positions of numbers Shows relative positions of numbers Allows for quick comparisons Allows for quick comparisons

How many siblings do you have?

Dot Plot Example