To be fair, I understand that you don't have knowledge of my background. So allow me to enlighten you.
Like most who work in LE and similar (firefighters, etc), we often hold several jobs to supplement our income, develop secondary career paths, etc.
I worked in manufacturing for 32 years alongside my 25 years in LE. Right out of engineering school, I worked at the Ford steering-systems facility in Indy for 16 years (before they closed the plant), where I held several jobs including running maintenance programs for the building, powerhouse and waste treatment plant. I used oil analysis for many applications when it came to gearbox drives, conveyor systems, etc. I earned my boiler operation certification there, as well as my Class III universal refrigeration certification.
Further, after Ford, I worked at Carrier for 16 years. There, I ran the quality lab where I was in charge of all equipment validation and annual certifications. I ran statistical process quality control programs for some of the production lines. I wrote DFMEAs, PFMEAs and DOEs. I was trained and qualified in SixSigma and Shainin Red X root cause analysis.
And I also authored this:
https://www.machinerylubrication.com/Read/30383/engines-oil-analysis
So, yes, this cop knows plenty about statistical analysis and I have a sound footing from which I criticize LSJr's approach to data analysis. He may know more about oil, but I assure you he is not displaying good knowledge of proper data analysis.
