Box and Whisker Plots A.K.A Box Plots
What makes up a box plot? #4 Lower/First Quartile #5 Upper/Third #2 Lower Extreme #1 Median #3 Upper Extreme ABOVE BELOW The box plot is placed either _________ or __________ a number line NOT ______ on the number line
middle in order middle lower middle upper #1: Median middle in order The ___________ value when the data is ______________ #2: Lower/First Quartile middle lower The ___________ value of the _________ half of the data #3: Upper/Third Quartile middle upper The ___________ value of the _________ half of the data
lowest highest difference upper lower #4: Lower Extreme lowest The ___________ value #5: Upper Extreme highest The ____________ value #6: Interquartile Range difference upper The _________________ between the _________ and ___________ quartiles. lower
Example #1
24, 20, 18, 25, 22, 32, 30, 29, 35, 30, 28, 24, 38 1st - put the data in order 4th - find the UQ 2nd - find the median 5th - find the Lower Extreme 3rd - find the LQ 6th - find the Upper Extreme 18 20 22 24 24 25 28 29 30 30 32 35 38 23 31 18 38 Lower _____ Extreme Upper _____ Extreme 23 31 Lower _____ Quartile Upper _____ Quartile 28 Median _____
18 38 23 31 28 Interquartile Range: - 31 23 = 8 Lower _____ Extreme Upper _____ Extreme 23 31 Lower _____ Quartile Upper _____ Quartile 28 Median _____ • • • • • 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Interquartile Range: upper quartile lower quartile - 31 23 = 8
Let’s look at our data set 18 20 22 24 24 25 28 29 30 30 32 35 38 LQ Median UQ 25% - a quarter What percent of the data falls between the Lower Extreme and the Lower Quartile? 25% - a quarter What percent of the data falls between the Lower Quartile and the Median? 25% - a quarter What percent of the data falls between the Median and the Upper Quartile? 25% - a quarter What percent of the data falls between The Upper Quartile and the Upper Extreme?
Example #2
32, 12, 38, 42, 54, 26, 18, 30, 50, 44 1st - put the data in order 4th - find the UQ 2nd - find the median 5th - find the Lower Extreme 3rd - find the LQ 6th - find the Upper Extreme 35 12 18 26 30 32 38 42 44 50 54 26 44 12 54 Lower _____ Extreme Upper _____ Extreme 26 44 Lower _____ Quartile Upper _____ Quartile 35 Median _____
12 54 26 44 35 Interquartile Range: - 44 26 = 18 Lower _____ Extreme Upper _____ Extreme 26 44 Lower _____ Quartile Upper _____ Quartile 35 Median _____ • • • • • 12 16 20 24 28 32 36 40 44 48 52 56 60 64 Interquartile Range: upper quartile lower quartile - 44 26 = 18
Finding Information From a Box Plot
5 7 7 - 3 = 4 8 - 2 = 6 Cannot be determined Cannot be determined 1. What is the median? _______ 7 2. What is the upper quartile? _______ Cannot be determined 3. How many people were surveyed? _______ 7 - 3 = 4 4. What is the IQR? ________ 8 - 2 = 6 5. What is the range of the data? ______ Cannot be determined 6. What is the mean? _________
12 1. What is the lower quartile? _______ 21 2. What is the upper quartile? _______ 22 - 8 = 14 3. What is the range of the data? _______ 21 - 12 = 9 4. What is the IQR? ________ 25% 5. What percent of the data falls between 8 and 12? ______ 50% 6. What percent of the data is more than 15? _________
Use the data in the table to create a box plot.