The 
th percentile 
is that value of 
, say 
,
which corresponds to a cumulative frequency
of 
, where 
is the sample size.
Percentile
See also
Percentile Rank, Quantile, QuartileExplore with Wolfram|Alpha
References
Kenney, J. F. and Keeping, E. S. "Percentile Ranks." §3.6 in Mathematics of Statistics, Pt. 1, 3rd ed. Princeton, NJ: Van Nostrand, pp. 38-39, 1962.Referenced on Wolfram|Alpha
PercentileCite this as:
Weisstein, Eric W. "Percentile." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Percentile.html