fa: Frequency of false alarms or false positives (FP).

Description Usage Format Details See Also


fa is the frequency of false alarms or false positives (FP) in a population of N individuals.




An object of class numeric of length 1.


Definition: fa is the frequency of individuals for which Condition = FALSE and Decision = TRUE (positive).

fa is a measure of incorrect classifications (type-I-errors), not an individual case.


  1. to probabilities: The frequency fa depends on the false alarm rate fart (aka. false positive rate, FPR) and is conditional on the prevalence prev.

  2. to other frequencies: In a population of size N the following relationships hold:

    • N = cond_true + cond_false (by condition)

    • N = dec_pos + dec_neg (by decision)

    • N = dec_cor + dec_err (by correspondence of decision to condition)

    • N = hi + mi + fa + cr (by condition x decision)

See Also

fart is the probability of false alarms (aka. false positive rate FPR or fallout); num contains basic numeric parameters; init_num initializes basic numeric parameters; freq contains current frequency information; comp_freq computes current frequency information; prob contains current probability information; comp_prob computes current probability information; is_freq verifies frequencies.

Other essential parameters: cr, hi, mi, prev, sens, spec

Other frequencies: N, cond_false, cond_true, cr, dec_cor, dec_err, dec_neg, dec_pos, hi, mi

riskyr documentation built on Jan. 3, 2019, 1:06 a.m.