new file mode 100644
--- /dev/null
+++ b/scripts/statistics/std.m
@@ -0,0 +1,30 @@
+function retval = std (a)
+
+# usage: std (a)
+#
+# For vector arguments, std returns the standard deviation of the
+# values.  For matrix arguments, std returns a row vector containing
+# the standard deviation for each column.
+#
+# See also: mean, median
+
+  if (nargin != 1)
+    error ("usage: std (a)");
+  endif
+
+  nr = rows (a);
+  nc = columns (a);
+  if (nc == 1 && nr == 1)
+    retval = 0;
+  elseif (nc == 1 || nr == 1)
+    tmp = sum (a);
+    n = length (a);
+    retval = sqrt ((n * sumsq (a) - tmp .* tmp) / (n * (n - 1)));
+  elseif (nr > 1 && nc > 0)
+    tmp = sum (a);
+    retval = sqrt ((nr * sumsq (a) - tmp .* tmp) / (nr * (nr - 1)));
+  else
+    error ("mean: invalid matrix argument");
+  endif
+
+endfunction