Category Archives: Statistics

US Manufacturing Employment Versus Time

The only television news program that I watch is the PBS Newshour. I particularly like the discussions between Mark Shields, a reasonable liberal, and David Brooks, a reasonable conservative. On inauguration day (20-Jan-2017), they had an interesting discussion about the challenges the US faces and what can be done about them. Continue reading

Posted in History Through Spreadsheets, Statistics | 4 Comments

Naked and Afraid Statistics

I do not watch much reality television, but one show I do watch is Naked and Afraid (N&A). I have always been interested in primitive survival skills (e.g. I have blogged about knot tying and rigging), and this show really puts those skills to the test. I like the fact that the participants are presented with survival challenges from around the world (Figure 1). They have been on all the continents but Antarctica – I could not imagine someone surviving naked in Antarctica for any length of time. Continue reading

Posted in Statistics | 15 Comments

MTBF and Annualized Failure Rates

One of the more distasteful tasks I need to do is make estimates of annual product failure rates using MTBF predictions based on part count methods. I find this task distasteful because I have never seen any indication that MTBF predictions are correlated in any way with field failure rates. This is not solely my observation – the US Army has cancelled its use of part count method MTBF predictions (i.e. based on MIL-HDBK-217). However, the telecommunications industry has continued to use these predictions through their use of SR-332. If you want to see a simple example of an SR-332-based reliability prediction, see this very clear example from Avago. Continue reading

Posted in Statistics | 3 Comments

Modeling Coal Energy Output

I had never seen coal until my first trip to China when I saw people on bicycles transporting coal to their homes for heat. I started to wonder just how much coal a home would need for heating. I have seen numerous values for the heat content of the various types of coal. I recalled from primary school that there were three types of coal: anthracite, bituminous, and lignite. So I would have expected three values for the heat output of coal. When I actually looked, I found dozens of grades of three primary types of coal. Each of the different grades would generate different amounts of heat per kilogram. I thought I would take a closer look at how the heat output from coal could be modeled using regression and a simplified model based on chemical heats of formation. Continue reading

Posted in General Science, Statistics | Leave a comment

Statistics Example from World War 2

I recently finished a course on Bayesian analysis from and I have been looking for application examples that will provide me with some experience using these methods. I like to compare the Bayesian solutions with the standard solutions (usually called Frequentist). Continue reading

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My Online Statistics Education Experience

Quote of the Day I can't mate in captivity. — Gloria Steinem on why she never married I have been fortunate in having worked for companies that have had enlightened education policies, which I have always taken advantage of. These … Continue reading

Posted in Statistics | 3 Comments

My ANOVA and Gage R&R Self-Education

Quote of the Day Who are a little wise the best fools be. — John Donne Introduction I recently took an excellent class at called "Prediction & Tolerance Intervals, Measurement and Reliability" taught by Dr. Tom Ryan, a former … Continue reading

Posted in Statistics | 2 Comments