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## Statistics and probability

### Course: Statistics and probability>Unit 4

Lesson 1: Percentiles

# Calculating percentile

AP.STATS:
UNC‑1 (EU)
,
UNC‑1.I (LO)
,
UNC‑1.I.5 (EK)
CCSS.Math:
Learn how to calculate the percentile rank for a given data point.

## Want to join the conversation?

• shouldn't it be 57.14% ?
• You're correct. He made a mistake when dividing 7 into 50.
• I can see how we just guess and check to see whether we should use method 1 or 2, but supposed this is on the Free Response section of the exam? How should we know which definition of percentile to use?
• Percentiles for finite and/or discrete data sets tend to be ambiguous, because there are multiple reasonable definitions of percentile that could give different answers. If you are given a free response question about percentiles and you are not told which definition to use, it is best to explain which definition you are using.

Have a blessed, wonderful day!
• At , shouldn't 7 go into 50 seven times, not five?
• Yes, Sal made a minor mistake. He thought that 4/7 equals 0.55 repeating. However 4/7 = 0.571428571. Hope this helped!
• Even though the answer is 57 % would you say the answer is 55 because that is the closest one?
• yes because 70 is much farther away than 55
• Sal made a mistake when caculating 4/7, hesaid that it was about 0.55, but it is actually 0.571428...
• Pretty sure that I saw a third way to calculate a percentile rank: counting data points below plus half of data points at the amount in question. Talk about ambiguity!
• Wait a minute, did Sal make a mistake for the calculation of 7 divided by 4.000? Because I am pretty sure it should have been around 0.57...