The interquartile range formula is the first quartile subtracted from the third quartile:
IQR = Q3 – Q1.**************************************************** Step 1: Put the numbers in order. 75, 78, 84, 91, 98
Step 2: Find the median. 75, 78, 84, 91, 98 Step 3: Place parentheses around the numbers above and below the median. Not necessary statistically, but it makes Q1 and Q3 easier to spot. (75, 78), 84, (91, 98) Step 4: Find Q1 and Q3 Think of Q1 as a median in the lower half of the data and think of Q3 as a median for the upper half of data. (75, 78), 84, (91, 98)
