comp_PPV

0th

Percentile

Compute a decision's positive predictive value (PPV) from probabilities.

comp_PPV computes the positive predictive value PPV from 3 essential probabilities prev, sens, and spec.

Usage
comp_PPV(prev, sens, spec)
Arguments
prev

The condition's prevalence prev (i.e., the probability of condition being TRUE).

sens

The decision's sensitivity sens (i.e., the conditional probability of a positive decision provided that the condition is TRUE).

spec

The decision's specificity value spec (i.e., the conditional probability of a negative decision provided that the condition is FALSE).

Details

comp_PPV uses probabilities (not frequencies) and does not round results.

Value

The positive predictive value PPV as a probability. A warning is provided for NaN values.

See Also

comp_sens and comp_NPV compute related probabilities; is_extreme_prob_set verifies extreme cases; comp_complement computes a probability's complement; is_complement verifies probability complements; comp_prob computes current probability information; prob contains current probability information; is_prob verifies probabilities.

Other functions computing probabilities: comp_FDR, comp_FOR, comp_NPV, comp_accu_freq, comp_accu_prob, comp_acc, comp_comp_pair, comp_complement, comp_complete_prob_set, comp_err, comp_fart, comp_mirt, comp_ppod, comp_prob_freq, comp_prob, comp_sens, comp_spec

Aliases
  • comp_PPV
Examples
# NOT RUN {
# (1) Ways to work:
comp_PPV(.50, .500, .500)  # => PPV = 0.5
comp_PPV(.50, .333, .666)  # => PPV = 0.499

# (2) Watch out for vectors:
prev <- seq(0, 1, .1)
comp_PPV(prev, .5, .5)  # => without NaN values
comp_PPV(prev,  0,  1)  # => with NaN values

# (3) Watch out for extreme values:
comp_PPV(prev = 1, sens = 0, spec = .5)  # => NaN, only mi: hi = 0 and fa = 0: PPV = 0/0 = NaN
is_extreme_prob_set(prev = 1, sens = 0, spec = .5)  # => verifies extreme cases

comp_PPV(prev = 0, sens = .5, spec = 1)  # => NaN, only cr: hi = 0 and fa = 0: PPV = 0/0 = NaN
is_extreme_prob_set(prev = 0, sens = .5, spec = 1)  # => verifies extreme cases

comp_PPV(prev = .5, sens = 0, spec = 1)  # => NaN, only cr: hi = 0 and fa = 0: PPV = 0/0 = NaN
is_extreme_prob_set(prev = .5, sens = 0, spec = 1)  # => verifies extreme cases


# }
Documentation reproduced from package riskyr, version 0.2.0, License: GPL-2 | GPL-3

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