How to create a Box and Whisker Plot Put Numbers in order from least to greatest 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56, Now with the paper in front of you put your numbers in order from least to greatest!!

Find the lowest number which is the lower extreme 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56 Find the lowest number which is the lower extreme Find the highest number which is the upper extreme. 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56, Lower Extreme = 12 Upper Extreme = 56 What is your Lower and Upper Extreme—fill out your paper!!

Now find the median. Now find the median on your paper!! 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56 Lower Extreme = 12 Upper Extreme = 56 Now find the median. 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56 2 numbers in middle means you have to add them together and divide by 2--- 32 + 34 = 66 / 2 = 33 Median = 33 Now find the median on your paper!!

Now find the middle of the bottom half of the numbers. 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56 Lower Extreme = 12 Upper Extreme = 56 Median=33 Now find the middle of the bottom half of the numbers. 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56 4numbers 4 numbers Lower Quartile = 23 What would you do if there were 2 middle numbers?-----Add them together and divide by 2 just like median. Now find your Lower Quartile!!

Now find the middle of the top half of the numbers. 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56 Lower Extreme = 12 Upper Extreme = 56 Median=33 Lower Quartile = 23 Now find the middle of the top half of the numbers. 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56 4numbers 4 numbers Upper Quartile = 42 What would you do if there were 2 middle numbers?-----Add them together and divide by 2 just like median. Now find your Upper Quartile!!

What would you count by for your number line? 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56 Lower Extreme = 12 Upper Extreme = 56 Median=33 Lower Quartile = 23 Upper Quartile = 42 Next make a number line with equal intervals, the numbers will be placed on this line. 10 15 20 25 30 35 40 45 50 55 60 What would you count by for your number line? You should say 2 starting at 10

Lower Extreme = 12 Upper Extreme = 56 This is called 12, 15, 16, 18, 23, 23, 23, 26, 32, 34, 34, 35, 37, 42, 45, 45, 46, 56 Lower Extreme = 12 Upper Extreme = 56 This is called Median=33 5 Number Summary Lower Quartile = 23 or Upper Quartile = 42 Measures of Variation Place dots above the numbers listed above as Box Points. 10 15 20 25 30 35 40 45 50 55 60 33 23 56 12 42 *Last draw a box around the 3 middle numbers and whiskers (lines) to the extremes or 2 outer numbers. Draw a straight line from top to bottom in middle of box at median. **This is the Same median as in Central Tendency**

Stop Don’t go forward until you have all your work done on the practice problem on your paper!!! When you are done we will check your answer on the next page!!!

Check your answer Here!! 10, 10, 12, 13, 13, 15, 15, 15, 15, 18, 19, 19, 20, 20, 25,25, 26, 30 15 + 18= 33/2= 16.5 Lower Extreme Median Upper Extreme Lower Quartile Upper Quartile 17 13 30 10 20 10 12 14 16 18 20 22 24 26 28 30 Ok one more step

19 is the Inter-Quartile Range of this Data You are now ready to find the interquartile range (IQR). The Inter-Quartile Range is the difference between the upper quartile and the lower quartile. In our case the IQR = 42 - 23 = 19. The IQR is a very useful measurement. It is useful because it is less influenced by extreme values, it limits the range to the middle 50% of the values. 19 is the Inter-Quartile Range of this Data                                                                                                                                                                                                                            What is the interquartiles range of your data? Upper Quartile 20 – Lower Quartile 13 = 7 IQR

Go to page 444 do 11 and 12 Follow these directions Go to page 444 do 11 and 12 Follow these directions. Find the Lower Extreme Upper Extreme Median Lower Quartile Upper Quartile Draw the Box & Whisker Plot Find the IQR