If you have the x-th percentile, the index from a sample of size n that corresponds to it is k := max { i - natural | i <= x*n/100 }. Algorithmically, this is to sort the array and take the element k := floor(x*n/100).
Chat with our AI personalities
A single number cannot have a percentile.A single number cannot have a percentile.A single number cannot have a percentile.A single number cannot have a percentile.
A percentile depends on the distribution of the observations, not the total number of observations.
Let x be a real number, such that 0 < x < 100. x-th percentile from a sample of n is number k such that k max(i - natural number | i < x.n/100).
You cannot. The 75th percentile is the value of a variable such that 75% of the observations are below that value and 25% are higher. The 75th percentile in the heights of adult women will be a measure of height whereas the 75th percentile in the income distribution in a country will be the level of income [in some currency unit] such that 75% of incomes in the country are lower. These examples illustrate that the 75th percentile can be a measurement in any unit and converting to a percentage makes no sense.
A standard deviation in statistics is the amount at which a large number of given values in a set might deviate from the average. A percentile deviation represents this deviation as a percentage of the range.