What does percentile measure?

• A. The maximum value in the dataset.
• B. The mean of the dataset.
• C. The proportion of data values that fall below a given point.
• D. The spread of data around the mean.

Answer: (C)

Percentile measures the position of a value within a data set, specifically the proportion of observations that fall at or below that value. It tells you, for any given threshold, what percentage of data are below it. This is different from the maximum (which only tells you the largest value), the mean (which summarizes central tendency), or the spread around the mean (which describes dispersion). Percentiles effectively partition the data into 100 equal parts, so the 25th percentile is the point below which 25% of the data fall, the median is the 50th percentile, and so on. To find a percentile, you order the data and identify the cutoff corresponding to the desired percentage, with possible interpolation between data points depending on the convention used.