Add effect size calculation

pyutils_sh/__init__.py

@@ -29,6 +29,8 @@
     Functions for aggregating different types of data from school exams (e.g. student grades)
 gaze
     Functions for analyzing gaze/eye-tracking data
+stats
+    Tools for calculating different types of statistics
 survey
     Tools for aggregating and analyzing data from different surveys
 utils
@@ -37,5 +39,6 @@
 
 import pyutils_sh.exam
 import pyutils_sh.gaze
+import pyutils_sh.stats
 import pyutils_sh.survey
 import pyutils_sh.utils

pyutils_sh/stats.py

@@ -0,0 +1,44 @@
+"""
+Tools for calculating different types of statistics, such as effect size 
+estimates.
+"""
+
+import numpy as np
+
+
+def cohens_d(g1_m, g1_sd, g1_n, g2_m, g2_sd, g2_n):
+    """
+    Calculate Cohen's d for two independent samples.
+    
+    This calculation involves taking the mean difference between groups, and 
+    dividing it by the pooled standard deviation.
+
+    Parameters
+    ----------
+    g1_m : float
+        Mean value for group 1.
+    g1_sd : float
+        Standard deviation for group 1.
+    g1_n : int
+        Sample size of group 1.
+    g2_m : float
+        Mean value for group 2.
+    g2_sd : float
+        Standard deviation for group 2.
+    g2_n : int
+        Sample size of group 2.
+
+    Returns
+    -------
+    d : float
+        Standardized effect size (Cohen's d) for the group difference.
+    """
+
+    mean_diff = g2_m - g1_m
+
+    sd_num = ((g1_n - 1)*np.square(g1_sd)) + ((g2_n - 1)*np.square(g2_sd))
+    sd_denom = g1_n + g2_n - 2
+
+    sd_pooled = np.sqrt(sd_num / sd_denom)
+
+    return mean_diff/sd_pooled

setup.py

@@ -1,7 +1,7 @@
 from setuptools import setup, find_packages
 
 setup(name='pyutils_sh',
-      version='1.1.0',
+      version='1.2.0',
       description='Assortment of Python utilities for my personal projects',
       url='https://github.com/sho-87/pyutils_sh',
       author='Simon Ho',