R/init_prob.R
fart.Rd
fart
defines a decision's false alarm rate
(or the rate of false positives): The conditional probability
of the decision being positive if the condition is FALSE.
fart
An object of class numeric
of length 1.
Understanding or obtaining the false alarm rate fart
:
Definition:
fart
is the conditional probability
for an incorrect positive decision given that
the condition is FALSE
:
fart = p(decision = positive | condition = FALSE)
or the probability of a false alarm.
Perspective:
fart
further classifies
the subset of cond_false
individuals
by decision (fart = fa/cond_false
).
Alternative names:
false positive rate (FPR
),
rate of type-I errors (alpha
),
statistical significance level,
fallout
Relationships:
a. fart
is the complement of the
specificity spec
:
fart = 1 - spec
b. fart
is the opposite conditional probability
-- but not the complement --
of the false discovery rate
or false detection rate FDR
:
FDR = p(condition = FALSE | decision = positive)
In terms of frequencies,
fart
is the ratio of
fa
divided by cond_false
(i.e., fa + cr
):
fart = fa/cond_false = fa/(fa + cr)
Dependencies:
fart
is a feature of a decision process
or diagnostic procedure and a measure of
incorrect decisions (false positives).
However, due to being a conditional probability,
the value of fart
is not intrinsic to
the decision process, but also depends on the
condition's prevalence value prev
.
Consult Wikipedia for additional information.
comp_fart
computes fart
as the complement of spec
prob
contains current probability information;
comp_prob
computes current probability information;
num
contains basic numeric parameters;
init_num
initializes basic numeric parameters;
comp_freq
computes current frequency information;
is_prob
verifies probabilities.
Other probabilities:
FDR
,
FOR
,
NPV
,
PPV
,
acc
,
err
,
mirt
,
ppod
,
prev
,
sens
,
spec
fart <- .25 # sets a false alarm rate of 25%
fart <- 25/100 # (decision = positive) for 25 out of 100 people with (condition = FALSE)
is_prob(fart) # TRUE
#> [1] TRUE