Using Workbench Command

WEIGHTED SPATIAL STATISTICS ON A METRIC FILE
   wb_command -metric-weighted-stats
      <metric-in> - the input metric

      [-area-surface] - use vertex areas as weights
         <area-surface> - the surface to use for vertex areas

      [-weight-metric] - use weights from a metric file
         <weight-metric> - metric file containing the weights

      [-column] - only display output for one column
         <column> - the column number or name

      [-roi] - only consider data inside an roi
         <roi-metric> - the roi, as a metric file

         [-match-maps] - each column of input uses the corresponding column
            from the roi file

      [-mean] - compute weighted mean

      [-stdev] - compute weighted standard deviation

         [-sample] - estimate population stdev from the sample

      [-percentile] - compute weighted percentile
         <percent> - the percentile to find

      [-sum] - compute weighted sum

      [-show-map-name] - print map index and name before each output

      For each column of the input, a single number is printed, resulting from
      the specified operation.  You must specify exactly one of -area-surface
      or -weight-metric.  Use -column to only give output for a single column.
      Use -roi to consider only the data within a region.  Exactly one of
      -mean, -stdev, -percentile or -sum must be specified.

      Using -sum with -area-surface (or -weight-metric with a metric containing
      similar data) is equivalent to integrating with respect to surface area.
      For example, if you want to find the surface area within an roi, do this:

      $ wb_command -metric-weighted-stats roi.func.gii -sum -area-surface
      midthickness.surf.gii