bmech_CI

 [CIlow, CIhigh, SE, CIw, stat] =  bmech_CI(data,type,alpha,normal) computes confidence interval for
 unidimension data 

 ARGUMENTS
  data   ...   r x c matrix where CI are computed columnwise
  type   ...   computes CI about mean (arithmetic) or median. Default mean.
  alpha  ...   significance level. Default 0.05
  normal ...   normality of data. 'Yes' or 'no'. In case of 'no' non parametric CI built 

 RETURNS
  CIlow  ...  lower limit of confidence interval
  CIhigh ...  upper limit of confidence interval
  SE     ...  standard error
  CIw    ...  half width of CI
  stat   ...  mean or median of data


 NOTES
 - for parametric data, CI built using standard formula :  xbar +/- t*(SD)/n
 - For non-parametric data. Approximate CI given using median and rank 
  (see Gibbons 1993 "Nonparametric statistics" table B)