To illustrate that summarizing important features off list of numbers provides more information than looking at an unordered list. 2. To explain the concept of the shape of a set of numbers and the vocabulary used to describe shapes, and why it is useful to know something about the shape. 3. To learn the details of how to construct stem-and-leaf plot, histograms and foxtrots and how to compute various numerical measures. To discuss what kinds of summaries are best for various kinds of measurements. Section 7. 1 Turning Data into Information Four kinds of useful information about a set of data: center, variability, shape and outlier Types of center: mean, median and mode (and their definitions) Types of variability: range, standard deviation and SIR (and their definitions) Types of shape: symmetric, skew to the left, skew to the right, individual and bimodal (and their definitions) Definition of outlier (unusual values):
Section 7. 2 Picturing Data Stem-and-leaf plot and how to make a stem-and-leaf plot Step 1: Create stems Step 2: Attach leaves Step 3: Order the leaves Histogram Step 1: Divide range of data into intervals. Step 2: Count how many values fall into each interval. (Create a frequency table) Step 3: Draw bar over each interval with height = count (or proportion). Section 7. 3 Five Useful Numbers: A Summary The five number summary (and how to find them) Definition of SIR (intrauterine range) CE on / 4 Booklet
How to make a booklet: 1. Draw horizontal (or vertical) line, label it with values from lowest to highest in data. 2. Draw rectangle (box) with ends at quartiles. 3. Draw line in box at value of median. 4. Compute SIR = distance between quartiles. 5. Compute 1 . 5(LLC); outlier is any value more than this distance from closest quartile. 6. Draw line (whisker) from each end of box extending to farthest data value that is not an outlier. (If no outlier, then to min and Max. ) 7. Draw asterisks to indicate he outliers.