How do you graphically show the heights of the students in your - - PowerPoint PPT Presentation

How do you graphically show the heights of the students in your class?

In this lesson you will learn how to construct box plots by finding the medians of the data.

Let’s Review Measures of Center Median (middle) – order the numbers from least to greatest and find the middle number 5 12 7 9 2 10 2 5 7 9 10 12 8 3 8 6 12 4 3 4 6 8 12

Let’s Review Measures of Center Range – the difference between the maximum and minimum values 14 – 5 = 9 5 6 9 12 14

Core Lesson Organize the data from least to greatest. 52 55 57 54 56 50 56 53 57 65 53 56 54 58 Heights of students in inches

Core Lesson To draw a box plot, you need 5 values: Minimum, Maximum, Median, Lower Quartile and Upper Quartile 50 52 53 53 54 54 55 56 56 56 57 57 58 64

What are quartiles?

Quartiles are values that divide the data set into fourths

Core Lesson Minimum = 50 50 52 53 53 54 54 55 56 56 56 57 57 58 65 Maximum = 65 Median = 55.5 Lower Quartile = 53 Upper Quartile = 57

Core Lesson Draw a number line that includes your minimum and maximum points.

50 52 54 56 58 60 62 64 48 66

Core Lesson Draw a point for the median. Then, draw points for the lower and upper quartiles.

50 52 54 56 58 60 62 64 48 66

Core Lesson Draw a box using the upper and lower quartiles as sides. Draw a line through the median.

50 52 54 56 58 60 62 64 48 66

Core Lesson Draw points for the minimum and maximum

• values. Connect the points to the box with a

line.

50 52 54 56 58 60 62 64 48 66

Core Lesson

50 52 54 56 58 60 62 64 48 66

Lower Quartile – Quartile 1 Upper Quartile – Quartile 3

What were all these dots again?

Minimum Value Maximum Value Median

A Common Misunderstanding Why isn’t the first dot the first quartile?

50 52 54 56 58 60 62 64 48 66

Lower Quartile – Quartile 1 Minimum Value

Core Lesson How is the data distributed?

50 52 54 56 58 60 62 64 48 66 1/4 of the data is in the lower quartile 1/4 of the data is in the upper quartile 1/2 of the data is in the box

Core Lesson What is the range of the data?

50 52 54 56 58 60 62 64 48 66

65 – 50 = 15

In this lesson you have learned how to construct box plots by finding the medians of the data.