I am currently working through the methodology in the fitdistrplus package documentation for Rstudio (fitdistrplus: An R Package for Fitting Distributions | Journal of Statistical Software)in order to assist me in finding a suitable fitted distribution to my data. I have 29 observations (so a relatively small dataset) of donations to a University, and have taken the logarithm of these. I have fit both Weibull and Normal distributions to this logged dataset using the fitdist
function, and am now using the gofstat
function to return the outcomes of the 3 tests specified in this function. When running the code chunk below, the test outcome is "not computed" for the cvmtest (cramer von mises) and the adtest (anderson darling). Is this due to my small sample size, and is ther anything I can change to produce a test result?
(Note fln1 and flw1 are the fitted weibull and normal distributions respectively).
ingof = gofstat(list(fln1, flw1), fitnames = c("Normal", "Weibull"))
ingof
ingof$kstest
ingof$cvmtest
ingof$adtest
The r console output
Goodness-of-fit statistics
Normal
Kolmogorov-Smirnov statistic 0.06122030
Cramer-von Mises statistic 0.01605683
Anderson-Darling statistic 0.13297621
Weibull
Kolmogorov-Smirnov statistic 0.08153736
Cramer-von Mises statistic 0.02123806
Anderson-Darling statistic 0.15927092
Goodness-of-fit criteria
Normal Weibull
Akaikes Information Criterion 154.8863 154.5585
Bayesian Information Criterion 157.9970 157.6692
> ingof$kstest
Normal Weibull
"not rejected" "not rejected"
> ingof$cvmtest
Normal Weibull
"not computed" "not rejected"
> ingof$adtest
Normal Weibull
"not computed" "not rejected"
Thank you