Download

Click when ready PowerPoint Presentation, PPT - DocSlides

pasty-toler | 2015-09-20 | General

. Whiteboardmaths.com. © 2004 - 2008 All rights reserved. Stand SW 100. In addition to the demos/free presentations in this area there are at least 8 complete (and . FREE. ) presentations waiting for download under the . ID: 134599

Click when ready PowerPoint Presentation, PPT - DocSlides

Views : 43

Direct Link:
Link:https://www.docslides.com/pasty-toler/click-when-ready
Embed code:

Tags : click-when-ready quartile median data box median quartile box data range inter quartiles plot 130 boys girls 140 plots spread find

Download this presentation

DownloadNote - The PPT/PDF document "Click when ready" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.

Presentations text content in Click when ready

Show

Slide1

Click when ready



Whiteboardmaths.com

Stand SW 100

In addition to the demos/free presentations in this area there are at least 8 complete (and

FREE

) presentations waiting for download under the

My Account

button. Simply register to download immediately.

Slide2

Median, Quartiles, Inter-Quartile Range and Box Plots.

Measures of Spread

Remember: The range is the measure of spread that goes with the mean.

Mean

= 7 + 5 + 2 + 7 + 6 + 12 + 10 + 4 + 8 + 9

= 7

Range = 12 – 2 = 10

Example

1. Two dice were thrown 10 times and their scores were added together and recorded. Find the mean and range for this data.7, 5, 2, 7, 6, 12, 10, 4, 8, 9

Slide3

Median, Quartiles, Inter-Quartile Range and Box Plots.

Measures of Spread

The range is not a good measure of spread because one extreme, (very high or very low value) can have a big affect. The measure of spread that goes with the median is called the inter-quartile range and is generally a better measure of spread because it is not affected by extreme values.

A reminder about the median

Slide4

Single middle value

Averages (The Median)

The

median

is the middle value of a set of data once the data has been

ordered

Example 1.

Robert hit 11 balls at Grimsby driving range. The recorded distances of his drives, measured in yards, are given below. Find the median distance for his drives.85, 125, 130, 65, 100, 70, 75, 50, 140, 95, 70

Median drive =

85 yards

50, 65, 70, 70, 75, 85, 95, 100, 125, 130, 140

Ordered data

Slide5

Two middle values so take the mean.

Averages (The Median)

The

median

is the middle value of a set of data once the data has been

ordered

Example 1.

Robert hit 12 balls at Grimsby driving range. The recorded distances of his drives, measured in yards, are given below. Find the median distance for his drives.85, 125, 130, 65, 100, 70, 75, 50, 140, 135, 95, 70

Median drive =

90 yards

50, 65, 70, 70, 75, 85, 95, 100, 125, 130, 135, 140

Ordered data

Slide6

Finding the median, quartiles and inter-quartile range.

12, 6, 4, 9, 8, 4, 9, 8, 5, 9, 8, 10

4, 4, 5, 6, 8, 8, 8, 9, 9, 9, 10, 12

Order the data

Inter-Quartile Range = 9 - 5½ =

3½

Example 1: Find the median and quartiles for the data below.

Lower Quartile = 5½

Upper Quartile = 9

Median = 8

Slide7

Upper Quartile = 10

Lower Quartile = 4

Median = 8

3, 4, 4, 6, 8, 8, 8, 9, 10, 10, 15,

Finding the median, quartiles and inter-quartile range.

6, 3, 9, 8, 4, 10, 8, 4, 15, 8, 10

Order the data

Inter-Quartile Range = 10 - 4 =

Example 2

: Find the median and quartiles for the data below.

Slide8

2, 5, 6, 6, 7, 8, 8, 8, 9, 9, 10, 15

Median = 8 hours and the inter-quartile range = 9 – 6 = 3 hours.

Battery Life

: The life of 12 batteries recorded in hours is:

2, 5, 6, 6, 7, 8, 8, 8, 9, 9, 10, 15Mean = 93/12 = 7.75 hours and the range = 15 – 2 = 13 hours.

Discuss the calculations below.

The

averages are similar but the measures of spread are significantly different since the extreme values of 2 and 15 are not included in the inter-quartile range.

Slide9

Median

Lower Quartile

Upper Quartile

Lowest Value

Highest Value

Box

Whisker

130

140

150

160

170

180

190

Boys

Girls

Box and Whisker Diagrams.

Box plots are useful for

comparing

two or more sets

of data like that shown below for heights of boys and girls in a class.

Anatomy of a Box and Whisker Diagram.

Box Plots

Slide10

Lower Quartile = 5½

Upper Quartile = 9

Median = 8

4, 4, 5, 6, 8, 8, 8, 9, 9, 9, 10, 12

Example 1

: Draw a Box plot for the data below

Drawing a Box Plot.

Slide11

Upper Quartile = 10

Lower Quartile = 4

Median = 8

3, 4, 4, 6, 8, 8, 8, 9, 10, 10, 15,

Example 2

: Draw a Box plot for the data below

Drawing a Box Plot.

Slide12

Upper Quartile = 180

Lower Quartile = 158

Median = 171

Question

: Stuart recorded the heights in cm of boys in his class as shown below. Draw a box plot for this data.

Drawing a Box Plot.

137, 148, 155, 158, 165, 166, 166, 171, 171, 173, 175, 180, 184, 186, 186

130

140

150

160

170

180

190

Slide13

The boys are taller on average.

Question: Gemma recorded the heights in cm of girls in the same class and constructed a box plot from the data. The box plots for both boys and girls are shown below. Use the box plots to choose some correct statements comparing heights of boys and girls in the class. Justify your answers.

Drawing a Box Plot.

130

140

150

160

170

180

190

Boys

Girls

The girls are taller on average.

The girls show less variability in height.