Part 1 of Statistical Sampling by Bruce Truitt
a Criminal Act?
Remember X? That Letter You Learned to Hate in College?
Posted to AuditSkills.com In July 2009
By Bruce Truitt
I am pushing 60. Recovering auditor. Working on my addictions to criteria, findings, and paper. Still play amateur baseball and professional rock 'n' roll. No idea what I want to be if I grow up. I also teach statistics. WAIT! WAIT! DON'T STOP READING! Don't judge me TOO harshly! I am NOT a criminal!
Sorry, didn't mean to yell. Thanks for not leaving the room. No, really. I truly appreciate it.
You see, I often find that reaction to this small confession fuses catatonia, revulsion, and prayer into an awkward social ooze. Its effect is deadly, not unlike hour-long renditions of "Lush Life," "The Chicken Dance," or "Feelings." Maybe I should just tell folks "I am a doctor" or even "I am an accountant." At least the conversation would continue, albeit with a turn to what ails you physically or fiscally.
I have assiduously researched the genesis of these abysses in social discourse. I have discovered direct and robust correlations (sorry, can't help it) between several ordered factors:
- The lion's share of my students, associates, colleagues, and friends are college graduates.
- As college graduates, virtually all of them had to take statistics. (Now there's a motivator!)
- Fewer than 5% of them remember anything from their statistics courses. (How's that for ROI?)
- Almost all of them put their statistics book at the top of the stack of items sold back to their collegiate bookstore. (Well, there was some ROI, I guess.)
- Those who did not had no idea where their stats book was. (Out of mind, out of sight.)
- All of them felt a strong sense of lower digestive tract cathartic relief when their "sadistics" final was over. (!!!)
So, bastioned by these "whats," and, being a card-carrying nerd, I probed the "whys." The results were, again, curiously linear (oops, I did it again):
- Their statistics course was taught by a non-native English speaker who mumbled some Klingon dialect while scribbling incomprehensible Sumerian hieroglyphics on the blackboard, with their backs to their defenseless prey. (Ye shall know the truth and the truth shall make you sleep!)
- Periodically they would turn around to wax ecstatic over the divine design of the theory and the eternal elegance of the mathematics. (Birth, death, infinity, standard deviation... It's all the same right?)
- All those present were absent yet recalled a misty, eerie out-of-body after-life aura baby-you-can-drive-my-Karma sorta thingy. (It was everything I could do to not mention past-life regression here. You're quite welcome.)
- Accompanying these euphoric transcendences was an odd weightlessness akin to "floating on a sea of Greek symbols and Latin letters." (Who says these languages are dead!)
I remember sharing their pain. Perhaps the most statistically significant (yuk, yuk!) recollection was that each chapter in the book was "an unknowable universe unto itself." Let me explain. Imagine moving the Berlin Wall to the Amazon jungle and then transforming (arrrgh!) that construct into a Mobius strip. You know there's something on the other side, but you can't go over or around it to see if there really is an "other" side or just a word-problem-induced hallucination, much less check your lack of understanding.
We really are going somewhere with this, I promise.
Then it hit me. The "crime" was that statistics was made more complicated than it had to be. But why?!?
I realized that in virtually all statistics books, the seed, the primum mobile, the Alpha-Omega, the thread, the DNA, the glue that ties it all together was revealed not at the beginning but somewhere between chapters 7 and 11. Not a convenient story. "The Formula," in fact—in many ways the only formula you really need—was so tardy in its presentation that it was buried under the collapsed Berlin Wall in the Amazon jungle, in a fetid, Faulknerian rot.
Wanna know what that formula is? Here ‘tis, though, given the foregoing, not in mathematical terms:
Sample Size = Confidence x Variation
Are you transformed now? I hope so, but what's it all about, Alfie? Stay tuned. Same bat-time. Same bat-channel!
Nerds of the world unite!
Bruce Truitt has 25+ years' experience in applied statistics and government auditing, with particular focus on quantitative methods and reporting in health and human services fraud, waste, and abuse. His tools and methods are used by public and private sector entities in all 50 states and 33 foreign countries and have been recognized by the National State Auditors Association for Excellence in Accountability.
He also teaches the US Government Auditor's Training Institute's "Practical Statistical Sampling for Auditors" course, is on the National Medicaid Integrity Institute's faculty, and taught Quantitative Methods in Saint Edward's University's Graduate School of Business.
Bruce holds a Master of Public Affairs from the LBJ School of Public Affairs, as well as Masters' Degrees in Foreign Language Education and Russian and East European Studies from The University of Texas at Austin.