Definition

Noun: A percentile is a statistical measure that indicates the value below which a given percentage of observations in a group of observations falls. It is one of the 99 points that divide a ranked data set into 100 equal parts.

Usage and Examples

A percentile is used to compare an individual score or value to a larger sample. For example, if a score is at the 90th percentile, it means it is higher than 90% of the scores in the data set.

Advanced Usage

• Percentile Rank: This refers to the percentage of scores in a distribution that a specific score is greater than or equal to. It is the inverse of finding a percentile value.
  • A percentile rank of 85 means that 85% of the scores are at or below that point.
• Percentile Point/Value: The actual data value that corresponds to a specific percentile.
  • The 50th percentile point is also known as the median.

Variants and Related Words

• Median (n): The 50th percentile; the middle value in an ordered data set.
• Quartile (n): The points that divide the data into four equal parts (the 25th, 50th, and 75th percentiles).
• Decile (n): The points that divide the data into ten equal parts (the 10th, 20th, 30th... percentiles).

Synonyms

• Centile: A direct synonym for percentile.
• Quantile: A broader term for values that divide a frequency distribution into equal groups (percentiles, quartiles, and deciles are all types of quantiles).

Related Phrases and Concepts

• Percentile Range: The difference between two specified percentiles (e.g., the interquartile range is the range between the 25th and 75th percentiles).
• To fall into the [X]th percentile: A common phrase describing a data point's position.
  • His income falls into the top tenth percentile.

Noun

1. (statistics) any of the 99 numbered points that divide an ordered set of scores into 100 parts each of which contains one-hundredth of the total