Freeware
We are also making available free software which compute simple
statistics or more complex psychometric
results using popular questionnaires. We have tried to focus on instruments where the original
questionnaire has been made freely available by
the authors!!
Equivalence Generator 
Computes a Two OneSided tTest (TOST) for independent and paired
samples. This allows us to test for equivalence as opposed to difference
(although this programme does both). 
DASS 21 Scoring & Interpretation
Generator 
The Depression Anxiety Stress Scales (DASS; Lovibond & Lovibond, 1995) is a freely available psychometric
test assessing Depression, Anxiety and Stress. There is a 42 item and 21 item
version of this instrument. This programme below will score and provide
interpretive guidelines for the 21 item version. 
PTSD Scoring &
Interpretation Generator 
The PTSD Checklist is a 17 item trauma symptom severity
checklist. This second version programme computes scores and
interprets according to both 'research rules' and 'DSMIV rules'. 
BDI Scoring &
Interpretation Generator 
The Beck Depression Inventory in a 21 item measure of depressive
symptomatology. This scorer will provide z scores, percentiles and a
category rating of the derived score. 
Very Average Generator 
This small application computes averages for up to 6 numbers
using both unweighted and weighted formulae. 
Standard
Deviation Generator 
This application will allow you to convert the standard error of
the mean into a standard deviation and also allow you to compute the
standard deviation from a given confidence interval (e.g., 95%
confidence intervals). 
ZScore & Percentile
Generator 
This application computes Zscores and percentiles for a mean
and standard deviation (SD). It will also convert between an SD and
a confidence interval and convert between a confidence interval and
a SD. It will also compute whether a score is significantly
different from a scale's mean (e.g., whether a score on a
questionnaire is significantly different from the mean). 
Prediction
Rate Success Generator 
This programme computes the likely number of true hits one would
get by chance if one randomly allocated individuals to one of two
groups. It is useful to compare your success rate compared to that
of chance. 
d'
(d Prime) Generator 
Inspired by Prof Jeff Lohr, this programme computes two types of
d'. In the first version (where no base rates are known), d' is the
standardised difference between a true signal and an untrue signal
(i.e., noise). The second version of d' computes probabilities of a
condition given the hits (true signals), false alarms (untrue
signals; i.e., noise), and base rates (how prevalent is the
condition). 
More to come ... References Beck, A.T., Ward, C. H., Mendelson, M., Mock, J., &&
Erbaugh, J. (1961). An inventory for measuring depression. Archives of
General Psychiatry, 4, 561571.
Lovibond,
S.H., & Lovibond, P.F. (1995). Manual for the Depression Anxiety Stress
Scales (2^{nd} Ed.). Sydney, Australia: Psychology Foundation of
Australia.
Weathers F, Huska J, and Keane T. (1991). The PTSD
Checklist Military Version (PCLM). Boston, Mass: National Center for
PTSD.
