scipy.stats.percentileofscore

scipy.stats.percentileofscore(a, score, kind='rank')

The percentile rank of a score relative to a list of scores.

A percentileofscore of, for example, 80% means that 80% of the scores in a are below the given score. In the case of gaps or ties, the exact definition depends on the optional keyword, kind.

Parameters:

a : array_like

Array of scores to which score is compared.

score : int or float

Score that is compared to the elements in a.

kind : {‘rank’, ‘weak’, ‘strict’, ‘mean’}, optional

This optional parameter specifies the interpretation of the resulting score:

• “rank”: Average percentage ranking of score. In case of

  multiple matches, average the percentage rankings of all matching scores.

• “weak”: This kind corresponds to the definition of a cumulative

  distribution function. A percentileofscore of 80% means that 80% of values are less than or equal to the provided score.

• “strict”: Similar to “weak”, except that only values that are

  strictly less than the given score are counted.

• “mean”: The average of the “weak” and “strict” scores, often used in

  testing. See

  http://en.wikipedia.org/wiki/Percentile_rank

Returns:

pcos : float

Percentile-position of score (0-100) relative to a.

See also

numpy.percentile

Examples

Three-quarters of the given values lie below a given score:

>>> from scipy import stats
>>> stats.percentileofscore([1, 2, 3, 4], 3)
75.0

With multiple matches, note how the scores of the two matches, 0.6 and 0.8 respectively, are averaged:

>>> stats.percentileofscore([1, 2, 3, 3, 4], 3)
70.0

Only 2/5 values are strictly less than 3:

>>> stats.percentileofscore([1, 2, 3, 3, 4], 3, kind='strict')
40.0

But 4/5 values are less than or equal to 3:

>>> stats.percentileofscore([1, 2, 3, 3, 4], 3, kind='weak')
80.0

The average between the weak and the strict scores is

>>> stats.percentileofscore([1, 2, 3, 3, 4], 3, kind='mean')
60.0