Description Usage Arguments Details Value Author(s) References See Also Examples
View source: R/summary.fechner.R
S3 method to summarize objects of the class fechner
.
1 2 |
object |
a required object of class |
level |
an optional numeric, integer-valued and greater than or equal to 2, giving the level of comparison of the S-index and the overall Fechnerian distance G. |
... |
further arguments to be passed to or from other methods. They are ignored in this function. |
The summary
method outlines the results obtained from
Fechnerian scaling analyses. It computes the Pearson correlation
coefficient and the C-index (see Uenlue, Kiefer, and
Dzhafarov (2009))
C = (2 * sum((S - G)^2)) / (sum(S^2) + sum(G^2))
for specific (controlled by the argument level
) stimuli pairs
with their corresponding S-index and G values.
The level
of comparison refers to the minimum number of links
in geodesic loops. That is, choosing level n means that
comparison involves only those S-index and G values that
have geodesic loops containing not less than n links.
If there are no (off-diagonal) pairs of stimuli with geodesic loops
containing at least level
links (in this case a summary is
not possible), summary.fechner
stops with an error message.
The function summary.fechner
returns an object of the class
summary.fechner
(see ‘Value’), for which a
print
method, print.summary.fechner
, is
provided. Specific summary information details such as individual
stimuli pairs and their corresponding S-index and G
values can be accessed through assignment (see ‘Examples’).
If the arguments object
and level
are of required
types, and if there are (off-diagonal) pairs of stimuli with
geodesic loops containing at least level
links,
summary.fechner
returns a named list, of the class
summary.fechner
, consisting of the following four components:
pairs.used.for.comparison |
a data frame giving the pairs
of stimuli (first variable |
Pearson.correlation |
a numeric giving the value of the Pearson correlation coefficient if it exists, or a character string saying “Pearson's correlation coefficient is not defined” if it does not exist. |
C.index |
a numeric giving the value of the C-index. |
comparison.level |
a numeric giving the |
Thomas Kiefer, Ali Uenlue. Based on original MATLAB source by Ehtibar N. Dzhafarov.
Dzhafarov, E. N. and Colonius, H. (2006) Reconstructing distances among objects from their discriminability. Psychometrika, 71, 365–386.
Dzhafarov, E. N. and Colonius, H. (2007) Dissimilarity cumulation theory and subjective metrics. Journal of Mathematical Psychology, 51, 290–304.
Uenlue, A. and Kiefer, T. and Dzhafarov, E. N. (2009) Fechnerian scaling in R: The package fechner. Journal of Statistical Software, 31(6), 1–24. URL http://www.jstatsoft.org/v31/i06/.
plot.fechner
, the S3 method for plotting objects of
the class fechner
; print.fechner
, the S3 method
for printing objects of the class fechner
;
print.summary.fechner
, the S3 method for printing
objects of the class summary.fechner
; fechner
,
the main function for Fechnerian scaling, which creates objects of
the class fechner
. See also fechner-package
for general information about this package.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | ## Fechnerian scaling of dataset \link{wish}
f.scal.wish <- fechner(wish)
## results are summarized for comparison levels 2 and 5
summary(f.scal.wish)
summary(f.scal.wish, level = 5)
## accessing detailed summaries through assignment
str(detailed.summary.l1 <- summary(f.scal.wish))
detailed.summary.l5 <- summary(f.scal.wish, level = 5)
detailed.summary.l5$pairs.used.for.comparison[1, ]
## to verify the obtained summaries
f.scal.wish$geodesic.loops
f.scal.wish$S.index
f.scal.wish$overall.Fechnerian.distances
|
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