Merge pull request #350 from PSLmodels/sampling-variability

Add tmd/examination/2022/sampling_variability.py script

tmd/examination/2022/sampling_variability.py

@@ -0,0 +1,46 @@
+"""
+Calculate hypothetical TMD-vs-SOI itax percentage differences
+using bootstrap sampling methods.
+"""
+
+import sys
+import numpy as np
+import pandas as pd
+
+BS_SAMPLES = 1000
+BS_RNSEED = 192837465
+
+ITX_MEAN = 2300
+TMD_CV = 0.0034
+SOI_CV = 0.0102
+
+
+def sampling_variability():
+    """
+    High-level logic of the script.
+    """
+    # specify rng and draw samples
+    rng = np.random.default_rng(seed=BS_RNSEED)
+    tmd = rng.normal(ITX_MEAN, TMD_CV * ITX_MEAN, BS_SAMPLES)
+    soi = rng.normal(ITX_MEAN, SOI_CV * ITX_MEAN, BS_SAMPLES)
+    pctdiff = 100 * (tmd / soi - 1)
+
+    # show results
+    print(f"ITX_MEAN,TMD_CV,SOI_CV = {ITX_MEAN:.1f} {TMD_CV:.4f} {SOI_CV:.4f}")
+    pd_mean = pctdiff.mean()
+    pd_stdv = pctdiff.std()
+    pd_cv = pd_stdv / pd_mean
+    print(
+        f"BS:pctdiff num,mean,stdev,cv(%) = {BS_SAMPLES:4d}  "
+        f"{pd_mean:9.3f}  {pd_stdv:7.3f}  {100 * pd_cv:6.2f}"
+    )
+    if BS_SAMPLES == 1000:
+        pdiff = np.sort(pctdiff)
+        print(f"BS:pctdiff median = {pdiff[499]:9.3f}")
+        print(f"BS:pctdiff 95%_ci = {pdiff[24]:9.3f} , {pdiff[974]:9.3f}")
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(sampling_variability())