120 Views

Download Presentation
## Displaying Distributions with Graphs

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**Display Shoe Size**Human Graph…….. Watch as the graph changes shape. Does the interpretation change also?**Stemplot**• Stem (all but the right most digit) • Leaf (the final digit) • Smallest on top to largest on bottom • Leaf in row to right in increasing order • Back-to-back stemplots compare two related distributions: read carefully!!!!!!! • Does not work well for large data sets with each stem holding lots of leaves.**Examples:**Stem-and-leaf of Exercise N = 48 Leaf Unit = 100 N* = 5 (30) 0 000000000000000000000011111111 18 0 222233333 9 0 4455 5 0 677 2 0 8 1 1 1 1 1 1 1 1 1 1 1 2 1 2 1 2 1 2 1 2 8**Forty students took a statistics examination having a**maximum of 50 points. The score distribution is given in the following stem-and-leaf plot.Stem-and-leaf of Scores on Exam N = 39Leaf Unit = 1.0 2 0 28 6 1 2245 17 2 01333358889(8) 3 00156679 14 4 22444466788 3 5 000**Dotplot**• Each observation is a dot above a number line to show the distribution of the variable.**Histogram**• Breaks the range of values into classesand displays only the count or percent of observations in each class. • Always chose classes of equal width. • Five classes is a good minimum but use your best judgment. What you don’t want are gaps (too many classes) or skyscrapers (too few)**Five number summary and Boxplots**• Minimum: smallest value • Q1: first quartile (25%) • M: median (middle number 50%) second quartile • Q3: third quartile • Maximum: largest value**Others**• Relative cumulative frequency plot • Time plot**Calculator Use and Graphs:**• Data: Tip of the nose to tip of the finger • 81 95 85 84 87 80 88 97 86 92 89 80 73 85 90 88 82 70 93