Math I Notes Box and Whisker Plots I
Math I - Notes Box and Whisker Plots I CAN create a box and whisker plot I CAN interpret a box and whisker plot A box and whisker plot is a data display that organizes data values into _4_ groups.
INTERPRETING Box and Whisker Plots - A box and whisker plot separates data into FOUR sections…The two parts of the box and two whiskers. All four sections contain about the same number of data values. **The lengths of the sections tell you how spread out the data are. **
The large box represents About half of the data Lower Quartile 264 370 Each whisker represents about 25% of the data Upper Quartile 452 459 Median 572 Each whisker represents about 25% of the data
Definitions: Lower Quartile - The _Median_ of the lower half Upper Quartile - The MEDIAN of the _Upper_ half Lower Extreme - The __smallest__ data value Upper Extreme - The greatest ___data___ value
Steps for creating a box and whisker plot: 1. Order your data from least to greatest 2. Find the median of your data 3. Find the quartiles of your data (the median of the upper and lower half) **When a data set has an odd number of values, do NOT include the median in either half of the data when determining the quartiles. ** 4. Find the extremes of your data (the least and greatest values) 5. Plot the median, quartiles, and extremes below a number line (USE A RULER TO MAKE SURE YOUR NUMBER LINE “TICK MARKS” ARE EVENLY SPACED!!) 6. Draw the box and the whiskers
Example: Create a box and whisker plot using this data: 7, 19, 6, 12, 5, 17, 6, 13 1 “order” 5 6 6 7 12 13 17 19 2 Find the Median = 7+12= 19 /2 = 9. 5 3 5 6 6 7 9. 5 12 13 17 19 Lower quartile=__6__ Upper quartile= ____15_____ 4 Lower extreme = ___5____ Upper extreme = ____19____ 5 6 9. 5 15 19
Create a box and whisker plot using this data: 14, 6, 13, 17, 1, 12, 9, 18. Show all 4 steps and work neatly below. 1. Order… 1, 6, 9, 12, 13, 14, 17, 18 2. Median… 12. 5 3. Lower Quartile= 7. 5 Upper Quartile = 15. 5 4. Lower Extreme = 1 Upper Extreme = 18 1 7. 5 12. 5 15. 5 18
Create a box and whisker plot using this data: 77, 99, 112, 85, 117, 68, 63. Show all 4 steps and work neatly below. 1. Order… 63, 68, 77, 85, 99, 112, 117 2. Median… 85 3. Lower Quartile = 68 Upper Quartile = 112 4. Lower Extreme = 63 Upper Extreme = 117 63 68 85 112 117
The box-and-whisker plots below show a class’ test scores for two tests. What conclusions can you make? • The ____UPPER EXTREMES___ are the same for both tests. • The median for the second test is ___LARGER___ than the median for the first test. • The __UPPER QUARTILE__ for the first test is the same as the _MEDIAN__ for the second test. • The scores for the _TEST 1_ are more spread out than the scores for the __TEST 2 __. • Both range (91 – 62 = _29_) and the interquartile range (84 – 74 = _10_) of the first test are __LARGER__ than the range (91 – 71 = _20_) and the interquartile range (88 – 80 = _8_) of the second test. • Inner quartile range is ______the difference between the upper quartile and the lower quartile______
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