add some mathematical functions ; mostly from the math lessons themselfs

math/r_pkg/r_stddev.py

@@ -0,0 +1,13 @@
+# helper for standard deviation
+# book page: 235
+# AGPL-3.0
+import numpy as np
+
+def r_stddev(lst: list, r_dtype) -> float:
+    r_arr = np.asarray(lst)
+    return float(np.std(r_arr, dtype=r_dtype))
+
+def implemenentation():
+    print(r_stddev(sorted([6,4,9,5,7,11,5,3,7,5,4]),float))
+
+implemenentation()