What is it?
The IQR describes the middle 50% of values when ordered from lowest to highest. To find the interquartile range (IQR), first find the median (middle value) of the lower and upper half of the data. These values are quartile 1 (Q1) and quartile 3 (Q3). The IQR is the difference between Q3 and Q1.
How do you find IQR?
<em>Step 1: Put the numbers in order. ...</em>
<em>Step 2: Find the median. ...</em>
<em>Step 3: Place parentheses around the numbers above and below the median. Not necessary statistically, but it makes Q1 and Q3 easier to spot. ...</em>
<em>Step 4: Find Q1 and Q3. ...</em>
<em>Step 5: Subtract Q1 from Q3 to find the interquartile range.</em>
If the distribution is uniform between 6 and 12, the probability of being less than 99 is 1 (certainty).
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Perhaps you intend to find the probability that the loss is less than 9 pounds. That value is
... (9 - 6)/(12 - 6) = 3/6 = 1/2
3,402
8% of 3150 is 252, 3150 + 252 = 3402.