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Extrapolating

We can use the same five steps to determine the 25th percentile if needed:

Step 1: The 25th percentile falls between the 10th and the 40th so our score must fall between 2 and 5.

Step 2: 40 – 10 = 30 percentiles or ticks

Step 3: Each tick is worth ( 5 – 2 ) / 30 or 3/30 or 1/10 (.1)

Step 4: We need either go up 15 from the 10th or down from the 40th. We’ll use the 10th as our starting place.

Step 5: See 3 charts on the slide