Question

How do you make a box and whisker plot?
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Answer 1

Hi. Sorry i'm 3 weeks late. I hope this will break it down for you.

Explanation:

First, you will need to determine the minimum value, lower quartile, median, upper quartile, and maximum value (Our 5 factors).

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(example)

The minimum is 1

The lower quartile is 3

The median is 6

The upper quartile is 9

The maximum value is 12

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Now we make a number line.

<----------------------------------------------------------------------------------------------->

0 1 2 3 4 5 6 7 8 9 10 11 12 13

____________________________________________________________We have our number line finished, so we have to start labeling where are factors are located. I will label them with an "o" above each one.

o o o o o

<----------------------------------------------------------------------------------------------->

0 1 2 3 4 5 6 7 8 9 10 11 12 13

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So, we got it all set. so now, we finish it off. We make a box, starting from the lower quartile and ending at the upper quartile like this. ( I could not make the full box, so I made a line above it.)

|------------------------------------------|

o o o o o

<----------------------------------------------------------------------------------------------->

0 1 2 3 4 5 6 7 8 9 10 11 12 13

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Then, we make a whisker from the minimum to the lower quartile, then the upper quartile to the maximum like shown.

______|------------------------------------------|____________

o o o o o

<----------------------------------------------------------------------------------------------->

0 1 2 3 4 5 6 7 8 9 10 11 12 13

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Then finally divide the box by the median.

______|------------------------------------------|____________

|

o o o o o

<----------------------------------------------------------------------------------------------->

0 1 2 3 4 5 6 7 8 9 10 11 12 13

____________________________________________________________

^

|

|

|

Your final product should look like the one above, except the fact that the box is NOT a line.

I hope you have a good day.

Answer 2

Explanation:

Notes Unit 8: Interquartile Range, Box Plots, and Outliers

I. Box Plot

A. What is it?

• Also called a ‘Box and Whiskers’ plot • A 5-numbered summary of data: • Lower extreme

• Lower quartile

• Median

• Upper quartile

• Upper extreme

• To draw a Box Plot, we need to find all 5 of these numbers

B. Steps to Creating a Box Plot

1. Order the numbers smallest to largest

2. Find the 5 numbers- median, lower and upper extremes, lower and upper quartiles

3 Draw the box plot- draw a number line, draw and label the parts

C. Examples

Example 1:

12, 13, 5, 8, 9, 20, 16, 14, 14, 6, 9, 12, 12 Step 1: Order the numbers from smallest to largest 5, 6, 8, 9, 9, 12, 12, 12, 13, 14, 14, 16, 20

Step 2 – Find the Median

5, 6, 8, 9, 9, 12, 12, 12, 13, 14, 14, 16, 20

Median: 12

2. Find the median. The median is

the middle number. If the data

has two middle numbers, find

the mean of the two numbers.

What is the median?

Step 2 – Find the Lower and Upper Extremes 5, 6, 8, 9, 9, 12, 12, 12, 13, 14, 14, 16, 20

Median: 12

5 20

2. Find the smallest and largest

numbers

Step 2 – Upper & Lower Quartiles 5, 6, 8, 9, 9, 12, 12, 12, 13, 14, 14, 16, 20

Median:

5 20

lower 12 quartile:

8.5

upper quartile: 14

3. Find the lower and upper medians or quartiles. These are the middle numbers on each side of the median. What are they?

Step 3 – Draw the Box Plot

Now you are ready to construct

the actual box & whisker plot. First

you will need to draw an ordinary

number line that extends far

enough in both directions to

include all the numbers in your

data:

Locate the main median 12 using a vertical line just above your number line:

Locate the lower median 8.5 and

the upper median 14 with similar

vertical lines:

Next, draw a box using the lower

and upper median lines as

endpoints:

Finally, the whiskers extend out to

the data's smallest number 5 and

largest number 20:

Name the parts of a Box-and-Whisker Plot

Lower Quartile Median Upper Quartile

Lower Extreme Upper Extreme3 1 2 II. Interquartile Range

The interquartile range is the

difference between the upper

quartile and the lower

quartile.

14 – 8.5 = 5.5

III. Outlier

A. What is it?

• An outlier is a number in a data set that is very different from the rest of the numbers. • It can have a MAJOR effect on the mean.

Totals of M&Ms:

19, 16, 17, 17, 19, 9

B. Finding Outliers

• Data: 10, 23, 6, 8, 9, 8

23

Outlier _____

C. The Effect of Outliers

Ex 1: Ms. Gray is 25 years old. She took a class with students who were 55, 52, 59, 61, 63, and 58 years old. Find the mean and median with and without Ms. Gray’s age.

Data with Ms. Gray’s age:

mean ≈ 53.3 median = 58

Data without Ms. Gray’s age:

mean = 58 median = 58.5

Ex 2: The Oswalds are shopping for gloves. They found 8 pairs of gloves with the following prices:

$17, $15, $3, $12, $13, $16, $19,

$19 Data with the outlier:

mean = $14.25 median = $15.50 Data without the outlier:

mean = 15.85 median = 16