discrim {sensR} | R Documentation |
Computes the d-prime, its standard error and P-value for the hypothesis of no sensory difference for any of four methods: 2-AFC, 3-AFC, duotrio and triangle tests.
discrim(success, total, method = c("duotrio", "threeAFC", "twoAFC", "triangle"), pd0 = 0, type = c("difference", "similarity"), ...)
success |
the number of correct answers |
total |
the total number of answers (sample size) |
method |
the discrimination protocol. Four allowed values: "twoAFC", "threeAFC", "duotrio", "triangle" |
pd0 |
the proportion of discriminators in the population of interest |
type |
the type of test |
... |
additional arguments passed to glm |
The p-value for the standard one-tailed difference test of "no
difference" is obtained with pd0 = 0
.
The probability under the null hypothesis is
given by pd0 + p0 * (1 - pd0)
where p0
is the guessing
probability defined by the method
argument.
The function uses the one of the dedicated binomial families and the
base function glm
An object of class discrim
with elements
coefficients |
named vector of coefficients (d-prime and tau) |
res.glm |
the glm-object from the fitting process |
vcov |
variance-covariance matrix of the coefficients |
se |
named vector with standard error of the coefficients (standard error of d-prime) |
data |
a named vector with the data supplied to the function |
p.value |
one-tailed exact binomial p-value |
test |
a string with the name of the test for the print method |
call |
the matched call |
Rune Haubo B Christensen and Per Bruun Brockhoff
Brockhoff, P.B. and Christensen, R.H.B (2010). Thurstonian models for sensory discrimination tests as generalized linear models. Food Quality and Preference, 21, pp. 330-338.
triangle
, twoAFC
,
threeAFC
, duotrio
,
discrimPwr
, discrimSim
,
discrimSS
, samediff
,
AnotA
, findcr
## Running the simple discrimination (differens) tests: discrim(10, 15, method = "twoAFC") discrim(10, 15, method = "threeAFC") discrim(10, 15, method = "duotrio") discrim(10, 15, method = "triangle") ## A similarity test where less than chance successes are obtained: discrim(20, 75, "triangle", pd0 = .2, type = "simil")