function?kappa（varargin）
%?KAPPA:?This?function?computes?the?Cohen‘s?kappa?coefficient.
%?Cohen‘s?kappa?coefficient?is?a?statistical?measure?of?inter-rater
%?reliability.?It?is?generally?thought?to?be?a?more?robust?measure?than
%?simple?percent?agreement?calculation?since?k?takes?into?account?the
%?agreement?occurring?by?chance.
%?Kappa?provides?a?measure?of?the?degree?to?which?two?judges?A?and?B
%?concur?in?their?respective?sortings?of?N?items?into?k?mutually?exclusive
%?categories.?A?‘judge‘?in?this?context?can?be?an?individual?human?being?a
%?set?of?individuals?who?sort?the?N?items?collectively?or?some?non-human
%?agency?such?as?a?computer?program?or?diagnostic?test?that?performs?a
%?sorting?on?the?basis?of?specified?criteria.
%?The?original?and?simplest?version?of?kappa?is?the?unweighted?kappa
%?coefficient?introduced?by?J.?Cohen?in?1960.?When?the?categories?are
%?merely?nominal?Cohen‘s?simple?unweighted?coefficient?is?the?only?form?of
%?kappa?that?can?meaningfully?be?used.?If?the?categories?are?ordinal?and?if
%?it?is?the?case?that?category?2?represents?more?of?something?than?category
%?1?that?category?3?represents?more?of?that?same?something?than?category
%?2?and?so?on?then?it?is?potentially?meaningful?to?take?this?into
%?account?weighting?each?cell?of?the?matrix?in?accordance?with?how?near?it
%?is?to?the?cell?in?that?row?that?includes?the?absolutely?concordant?items.
%?This?function?can?compute?a?linear?weights?or?a?quadratic?weights.
%
%?Syntax:?	kappa（XWALPHA）
%??????
%?????Inputs:
%???????????X?-?square?data?matrix
%???????????W?-?Weight?（0?=?unweighted;?1?=?linear?weighted;?2?=?quadratic
%???????????weighted;?-1?=?display?all.?Default=0）
%???????????ALPHA?-?default=0.05.
%
%?????Outputs:
%???????????-?Observed?agreement?percentage
%???????????-?Random?agreement?percentage
%???????????-?Agreement?percentage?due?to?true?concordance
%???????????-?Residual?not?random?agreement?percentage
%???????????-?Cohen‘s?kappa?
%???????????-?kappa?error
%???????????-?kappa?confidence?interval
%???????????-?Maximum?possible?kappa
%???????????-?k?observed?as?proportion?of?maximum?possible
%???????????-?k?benchmarks?by?Landis?and?Koch?
%???????????-?z?test?results
%
%??????Example:?
%
%???????????x=[88?14?18;?10?40?10;?2?6?12];
%
%???????????Calling?on?Matlab?the?function:?kappa（x）
%
%???????????Answer?is:
%
%?UNWEIGHTED?COHEN‘S?KAPPA
%?--------------------------------------------------------------------------------
%?Observed?agreement?（po）?=?0.7000
%?Random?agreement?（pe）?=?0.4100
%?Agreement?due?to?true?concordance?（po-pe）?=?0.2900
%?Residual?not?random?agreement?（1-pe）?=?0.5900
%?Cohen‘s?kappa?=?0.4915
%?kappa?error?=?0.0549
%?kappa?C.I.?（alpha?=?0.0500）?=?0.3839?????0.5992
%?Maximum?possible?kappa?given?the?observed?marginal?frequencies?=?0.8305
%?k?observed?as?proportion?of?maximum?possible?=?0.5918
%?Moderate?agreement
%?Variance?=?0.0031?????z?（k/sqrt（var））?=?8.8347????p