0-12 Stem and Leaf Plots Measures of Central Tendency Goals: Make and use a stem-and-leaf plot. Find the mean, median and mode of data. Eligible Content: A1.2.3.2.1 / A1.2.3.2.2

Vocabulary Data – information, facts or numbers that describe something. Bar Graph – compares different categories of data by showing each category as a bar whose length is related to the frequency. Line Graph – a graph used to show how data changes over time.

Vocabulary Stem and Leaf Plot – an arrangement of digits that is used to display and order numerical data. Example: Stem Leaves 2 4 6 6 9 3 0 4 7 4 1 2 2 5 7 9 5 2 4 5 5 8 Key: 2|4 = 24

Important things to remember about a Stem and Leaf Plots: Leaves are always only one digit. Leaves are always in order from smallest to largest. Leaves are NOT separated by commas!! Stems are always in order from smallest to largest. When listing the stems do NOT skip numbers. There should always be a key!

Make a Stem and Leaf Plot Ages of 24 patients at a health clinic: 25, 12, 30, 20, 15, 21, 16, 13, 18, 27, 43, 23, 19, 22, 20, 67, 53, 19, 25, 66, 35, 11, 20, 37 Stem Leaves 1 2 3 4 5 6 Key: 1|2 = 12

Examples Pick random numbers from 0 – 50. Use current grades.

Hey diddle diddle, the cat and the fiddle, The cow jumped over the moon. The little dog laughed to see such a sport And the dish ran away with the spoon!

Vocabulary Mean – average of the numbers in the data To find mean: Add all numbers and divide by how many there are! Median – the middle number when the numbers are in order To find median: Put numbers in order and find the middle. If there are 2 numbers in the middle, find the mean between them.

Vocabulary Mode – the number that appears most often Range – the difference between the largest number and the smallest number.

Find the mean, median and mode Inches of snowfall in 14 towns: 8, 4, 7, 6, 5, 6, 7, 3, 8, 11, 10, 5, 8, 4 Mean: total = 92 divided by 14 = 6.57 Median: 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 8, 10, 11 Mode: 6.57 inches 6.5 inches 8 inches

Examples Find the mean, median, mode and range: 85, 90, 92, 91, 86, 90 89, 90, 90, 7 7, 8, 10, 12, 6, 8, 9, 8, 9, 11, 9, 8, 12 9, 9, 8, 6 60, 62, 57, 59, 58, 60, 55, 60, 56, 54 58.1, 58.5, 60, 8

Practice Worksheet – “6.6 Practice A”

Homework Pages P39-P40 #1-6 Page P45 #4,5 (make a stem and leaf plot only)