- statistics: h = bartlett_test (x)
- statistics: h = bartlett_test (x, group)
- statistics: h = bartlett_test (x, alpha)
- statistics: h = bartlett_test (x, group, alpha)
- statistics: [h, pval] = bartlett_test (…)
- statistics: [h, pval, chisq] = bartlett_test (…)
- statistics: [h, pval, chisq, df] = bartlett_test (…)
 Perform a Bartlett test for the homogeneity of variances.
 Under the null hypothesis of equal variances, the test statistic chisq
 approximately follows a chi-square distribution with df degrees of
 freedom.
 The p-value (1 minus the CDF of this distribution at chisq) is
 returned in pval.  h = 1 if the null hypothesis is rejected at
 the significance level of alpha.  Otherwise h = 0.
 Input Arguments:
 
- 
 x contains the data and it can either be a vector or matrix.
 If x is a matrix, then each column is treated as a separate group.
 If x is a vector, then the group argument is mandatory.
 NaN values are omitted.
 
- 
 group contains the names for each group.  If x is a vector, then
 group must be a vector of the same length, or a string array or cell
 array of strings with one row for each element of x.  x values
 corresponding to the same value of group are placed in the same group.
 If x is a matrix, then group can either be a cell array of
 strings of a character array, with one row per column of x in the same
 way it is used in anova1function.  If x is a matrix, then
 group can be omitted either by entering an empty array ([]) or by
 parsing only alpha as a second argument (if required to change its
 default value).
- 
 alpha is the statistical significance value at which the null
 hypothesis is rejected.  Its default value is 0.05 and it can be parsed
 either as a second argument (when group is omitted) or as a third
 argument.
 
 See also: 
  levene_test, 
  vartest2, 
  vartestn
Source Code: 
  bartlett_test