Notes: Finding Quartiles & Interquartile range in a Data Set

Step 1: Put the numbers in order from least to greatest 4, 6, 9, 10, 17, 19, 21 . Step 2: Find the median(the number in the middle) 4, 6, 9, 10,17, 19, 21 Md = 10 . Step 3: Find the 1st or lower Quartile (median of the lower half) 4, 6, 9 so.. 1st Q = 6. Step 4: Find the 3rd or upper quartile (median of the upper half) 17, 19, 21 3rd Q = 19 ................
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