Percentile - Alternative Methods

Alternative Methods

Some software packages, including Microsoft Excel (up to the version 2007) use the following method, noted as an alternative by NIST to estimate the value, of the P-th percentile of an ascending ordered dataset containing N elements with values .

The rank is calculated:

and then split into its integer component k and decimal component d, such that . Then is calculated as:

v_P = \begin{cases} v_1, & \mbox{for }n=1 \\ v_N, & \mbox{for }n=N \\ v_k+d(v_{k+1}-v_k), & \mbox{for }1 < n < N \end{cases}

The primary method recommended by NIST is similar to that given above, but with the rank calculated as

These two approaches give the rank of the 40th percentile in the above example as, respectively:

and

.

The values are then interpolated as usual based on these ranks, yielding 29 and 26, respectively, for the 40th percentile.

Read more about this topic:  Percentile

Famous quotes containing the words alternative and/or methods:

    “If English is spoken in heaven ... God undoubtedly employs Cranmer as his speechwriter. The angels of the lesser ministries probably use the language of the New English Bible and the Alternative Service Book for internal memos.”
    —Charles, Prince Of Wales (b. 1948)

    “I think it is a wise course for laborers to unite to defend their interests.... I think the employer who declines to deal with organized labor and to recognize it as a proper element in the settlement of wage controversies is behind the times.... Of course, when organized labor permits itself to sympathize with violent methods or undue duress, it is not entitled to our sympathy.”
    —William Howard Taft (1857–1930)