Stemplots and Dotplots LESSON 1.2

Stem and Leaf Plots A kind of display that shows data in a structured form. **To construct, Leaf: first digit on the right Stem: the remaining digit or digits 624 stemleaf

41, 26, 27, 33, 18, 27, 30, 31, 31, 33, 6, 41, 40, 28, 39, 29, 40, 9, 40, 8 Example 1 leaf 0 stem , 8, 9 8 6, 7, 7, 8, 9 0,1, 1, 3, 3, 9 0, 0, 0, 1, 1 Key: 1|8 means 18

The ages of the Wimbleton tennis champions in the men’s and women’s singles from 1970 to 1990 are shown below. The dot (*) between two stems breaks the stem into two parts (ie , 25-29). Find the range of ages for the men and the women. Are there any outliers? If so, what are their ages? * Women 1 2 * 3 9,9,9 0,1,1,2 5,6,6,7,7,8,8,8,9,9 0,1,1,3 Key: 1|8 means 18 Men * 8,7 4,4,4,3,2,2,2,2,1,1,1 9,7,7,6,5, No!

Pets that each student has in a classroom *How many students are in the class? *What’s the frequency of students having 3 pets? *What is the mean?

LESSON 1.3 Measures of Center

Definitions Summation Notation: called “Sigma Notation” The sum of f sub i’s as i goes from 3 to 8. Mean:

Example 1 3 Height in inches 1 # of players a.How many members does the team have? a.Find the mean height? b.Find the median height? a.Which number best describes the typical height of a member of the team? Why? The median – the mean is skewed because of 79.

Example 2 A class has 20 students. Let g 1 = the test grade of the ith student. A. Use ∑ notation to express the total of the test grades for the class. B. What does represent? The mean of the test scores.

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