TTEST (paired) t-test
     For a sample X from a normal distribution with unknown mean and
     variance, perform a t-test of the null hypothesis `mean (X) == M'.
     Under the null, the test statistic T follows a Student
     distribution with `DF = length (X) - 1' degrees of freedom.

     TTEST treads NaNs as "Missing values" and ignores these. 

 H = ttest(x,m)
	tests Null-hypothesis that mean of x is m. 		
 H = ttest(x,y)
 	size of x and size of y must match, it is tested whether the 
	difference x-y is significantly different to m=0; 
 H = ttest(x,y,alpha)
 H = ttest(x,y,alpha,tail)
 H = ttest(x,y,alpha,tail,DIM)
 [H,PVAL] = ttest(...)
 [H,PVAL,CI] = ttest(...)
 [H,PVAL,CI,stats] = ttest(...)

     H=1 indicates a rejection of the Null-hypothesis at a significance 
     level of alpha (default alpha = 0.05).	 
 
     With the optional argument string TAIL, the alternative of interest
     can be selected.  If TAIL is '!=' or '<>' or 'both', the null is tested
     against the two-sided Alternative `mean (X) ~= mean (Y)'.  If TAIL
     is '>' or 'right', the one-sided Alternative `mean (X) > mean (Y)' is used.
     Similarly for '<' or 'left', the one-sided Alternative `mean (X) < mean
     (Y)' is used.  The default is the two-sided case.
 
     H returns whether the Null-Hypotheses must be rejected. 
     The p-value of the test is returned in PVAL. 
 
     TTEST works on the first non-singleton dimension or on DIM. 

     If no output argument is given, the p-value of the test is
     displayed.

Package: nan