cond.true: Number of individuals for which the condition is true.

Description Usage Format Details References See Also Examples

Description

cond.true is a frequency that describes the number of individuals in the current population N for which the condition is TRUE (i.e., actually true cases).

Usage

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Format

An object of class numeric of length 1.

Details

Key relationships:

  1. to probabilities: The frequency of cond.true individuals depends on the population size N and the condition's prevalence prev and is split further into two subsets of hi by the sensitivity sens and mi by the miss rate mirt.

    Perspectives:

    1. by condition:

      The frequency cond.true is determined by the population size N times the prevalence prev:

      cond.true = N x prev

    2. by decision:

      a. The frequency hi is determined by cond.true times the sensitivity sens (aka. hit rate HR):

      hi = cond.true x sens

      b. The frequency mi is determined by cond.true times the miss rate mirt = (1 - sens):

      mi = cond.true x mirt = cond.true x (1 - sens)

  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)

Current frequency information is computed by comp_freq and contained in a list freq.

References

Consult Wikipedia: Confusion matrix for additional information.

See Also

is_freq verifies frequencies; 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.

Other frequencies: N, cond.false, cr, dec.cor, dec.err, dec.neg, dec.pos, fa, hi, mi

Examples

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cond.true <- 1000 * .10   # => sets cond.true to 10% of 1000 = 100 cases.
is_freq(cond.true)        # => TRUE
is_prob(cond.true)        # => FALSE, as cond.true is no probability (but prev and sens are)

riskyr documentation built on Feb. 19, 2018, 5 p.m.