William M. Briggs

Statistician to the Stars!

Don’t Use Statistics Unless You Have To

It's catching.

It’s catching. (Image source.)

We’re finally getting it, as evinced by the responses to the article “Netherlands Temperature Controversy: Or, Yet Again, How Not To Do Time Series.

Let’s return to the Screaming Willies. Quoting myself (more or less):

You’re a doctor (your mother is proud) and have invented a new pill, profitizol, said to cure the screaming willies. You give this pill to 100 volunteer sufferers, and to another 100 you give an identically looking placebo.

Here are the facts, doc: 72 folks in the profitizol group got better, whereas only 58 in the placebo group did.

Now here is what I swear is not a trick question. If you can answer it, you’ll have grasped the true essence of statistical modeling. In what group were there a greater proportion of recoverers?

This is the same question that was asked [before], but with respect to…temperature values. Once we decided what was meant by a “trend”—itself no easy task—the question was: Was there a trend?

May I have a drum roll, please! The answer to today’s question is—isn’t the tension unbearable?—more people in the profitizol group got better.

Probability models aren’t needed: the result is unambiguously 100% certain sure.

As before, I asked, what caused the difference in rates? I don’t know and neither do you. It might have been the differences due to profitizol or it might be due to many other things about which we have no evidence. All we measured was who took what substance and who got better.

What caused the temperature to do what it did? I don’t know that either. Strike that. I do know that it wasn’t time. Time is not a cause. Fitting any standard time series model is thus admitting that we don’t know what the cause was or causes were. This is another reason only to use these models in a predictive manner: because we don’t know the causes. And because we don’t know the causes, it does not follow that the lone sole only cause was, say, strictly linear forcing. Or some weird force that just happened to match what some smoother (running means, say) produced.

Probability isn’t needed to say what happened. We can look and see that for ourselves. Probability is only needed to say what might yet happen (or rather, to say things about that which we haven’t yet observed, even though the observations took place in the past).

Probability does not say why something happened.

I pray that you will memorize that statement. If everybody who used probability models recited that statement while standing at attention before writing a paper, the world would be spared much grief.

In our case, is there any evidence profitizol was the cause of some of the “extra” cures? Well, sure. The difference itself is that evidence. But there’s no proof. What is there proof of?

That it cannot be that profitizol “works” in the sense that everybody who gets it is cured. The proof is the observation that not everybody who got the drug was cured. There is thus similar proof that the placebo doesn’t “work” either. We also know for sure that some thing or things caused each person who got better to get better, and other causes that made people who were sick to stay sick. Different causes.

Another thing we know with certainty: that “chance” didn’t cause the observed difference. Chance like time is not a cause. That is why we do not need probability models to say what happened! Nothing is ever “due” to chance!

This is why hypothesis testing must go, must be purged, must be repulsed, must be shunned, must be abandoned, must be left behind like an 18-year-old purges her commonsense when she matriculates at Smith.

Amusingly for this set of data a test of proportions gives a p-value of 0.054, so a researcher who used that test would write the baseless headline, “No Link Between Profitizol And The Screaming Willies!” But if the researcher had used logistic regression, the p-value would have been 0.039, which would have seen the baseless headline “Profitizol Linked To Screaming Willies Cure!”

Both researchers would falsely think in terms of cause, and both would be sure that cause was or wasn’t present. Like I said, time for hypothesis testing to die the death it deserves. Bring out the guillotine.

Since this is the week of Thanksgiving, that’s enough for now.

Summary Against Modern Thought: God Is Not A Body

This may be proved in three ways. The first...

This may be proved in three ways. The first…

See the first post in this series for an explanation and guide of our tour of Summa Contra Gentiles. All posts are under the category SAMT.

Previous post.

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Chapter 27: That God Is Not In The Form Of A Body

1 ACCORDINGLY, having shown that God is not the being of all,i it can be proved in like manner that God is not the form of any thing.

2 For the divine being cannot be the being of a quiddity that is not it own being, as shown above.[1] Now that which is the divine being itself is no other than God. Therefore it is impossible for God to be the form of any other thing.ii

3 Further. The form of a body is not its very being but the principle of its being. But God is being itself. Therefore God is not the form of a body.

4 Again. The union of form and matter results in a composite, and this is a whole in respect of form and matter. Now the parts are in potentiality with respect to the whole: but in God there is no potentiality.[2] Therefore it is impossible for God to be the form united to any thing.

5 Again. That which has being per se, is more excellent than what has being in another. Now every form of a body has being in another. Since then God is the most excellent being, as the first cause of being,[3] He cannot be the form of any thing.iii

6 Moreover, this can also be proved from the eternity of movement, as follows.[4] If God were the form of a movable thing, since He is the first mover, the composite will be its own mover. But that which moves itself can be moved and not moved. Therefore it is in it to be either. Now a thing of this kind has not of itself indefectibility of movement. Therefore above that which moves itself we must place something else as first mover, which confers on it perpetuity of movement. And thus God Who is the first mover is not the form of a body that moves itself.iv

7 This argument avails for those who hold the eternity of movement. Yet if this be not granted the same conclusion may be drawn from the regularity of the heavenly movement. For just as that which moves itself can both be at rest and be moved, so can it be moved with greater or less velocity. Wherefore the necessity of uniformity in the heavenly movement depends on some higher principle that is altogether immovable, and that is not the part, through being the form, of a body which moves itself.v

8 The authority of Scripture is in agreement with this truth. For it is written in the psalm:[5] Thy magnificence is elevated above the heavens; and (Job xi. 8, 9): He is higher than heaven, and what wilt thou do?…the measure of Him is longer than the earth, and deeper[6] than the sea.vi

——————————————————-

iGod is not the universe. Pantheism is out.

iiAs proved before, God’s existence and essence are the same; existence itself is not a body; a body is partly in act, partly in potential, but in God there is no potential; just as God is not made of material stuff; thus God is not a body. These same (now proven) premises are picked up in arguments 3 and 4.

iiiThe thing to recall here is that objects, like bodies, are composites of form and matter. The same matter under the “influence” of other forms is a different object; i.e. objects are instantiated forms. Ed Feser’s favorite example (now forever stuck in my head) is rubber balls and erasers: two objects made of the same matter, but with different forms. But God is not made of matter, and God’s form is His existence, therefore He is not a body.

ivWe ever come back to Chapter 13, which is best to review. So much flows from the demonstration that God is Unmoved Mover, the Uncaused Cause, and other nicknames, that it is astonishing. The proof here flows directly (and easily).

vIt’s as well here as anywhere to remind us of the kind of movement Aquinas spoke of in his proof of God being the First Cause. He was not talking about the kind of movement like dominoes, where one pushes another and so on. He meant the here-and-now bottom-down ultimate cause of all movement. If you can’t remember this distinction, do the review before commenting.

viI normally leave the scriptural arguments out because they are not convincing to modern audiences. However in this case, since the question has often arise that since Jesus was in the form of a body, and in the Eucharistic species, and that Jesus is part of the Trinity, i.e. is God, does it not follow that God is a body? It does not. Jesus is God, and had a fully divine nature. But he was also a man and had a human nature, a nature that required a body. That part of him was not divine; it was human flesh, just like ours. The Eucharistic is likewise of two natures, divine and mundane. The bread is there, but do is the divine. Now how are these miracles brought about? I haven’t the slightest idea.

Likewise, when scripture uses figurative or metaphorical language (“Seated a the right hand of God…”), it is just that: figurative or metaphorical. Avoid the atheist temptation to read all of the Bible literally.

[1] Ch. xxii.
[2] Ch. xvi.
[3] Ch. xiii.
[4] Cf. chs. xiii., xx.
[5] Ps. viii. 2.
[6] Vulg., broader.
[7] Sum. Th. P. I., Q. iii., A. 8.

On That New “Gay Gene” Study

From the paper, to show how noisy this data is.

From the paper, to show how noisy this data is.

First and most important point: there is no way we’re going to cover in 750 words the whole of this field. Much will be left out. This small article is not going to be all things; it will discuss only one important point. Experience suggests I should warn certain readers of the danger of hyperventilating and apoplexy.

If same-sex attraction is heritable, which is to say genetic, how is it that this trait has been passed along? Men who are SSA and act on these proclivities are far less likely to pass on their genes. Yet we have been assured that SSA has always been with us as a race; that is, for thousands of years over many, many generations. But not everywhere. Certain areas of Africa report no SSA men. Of course, some men with SSA mate with women, but not nearly at the same rate men not so afflicted. Thus whatever genetic components to SSA exist should gradually disappear. Or already be gone.

The new peer-reviewed study “Genome-wide scan demonstrates significant linkage for male sexual orientation” by A. R. Sanders and a slew of others in journal Psychological Medicine suggests an answer to this puzzler. “Our findings may also begin to provide a genetic basis for the considerable evolutionary paradox that homosexual men are less motivated than heterosexual men to have procreative sex and yet exist as a stable non-trivial minority of the population,” they say.

The word “considerable” is apt, and an understatement; but you have to admire the euphemism “less motivated.” Anyway, they correctly note the observed population stability of men with SSA. This is important, this observation, because it highlights that we should be finding a theory which fits these facts and not finding facts which fit a theory. Now one particular gene that these authors noted is shared by some (not all) SSA brothers (and some half brothers) is called “Xq28″. Never mind why.

The authors state, “Linkage to Xq28 is especially relevant to the X-linked sexually antagonistic selection hypothesis that women with genetic variant/s predisposing to homosexuality in men have a reproductive advantage compared with other women, i.e. that fertility costs of variants that increase the likelihood of a man’s homosexuality are balanced by increased fecundity when expressed in a woman”.

In other words, this appears to be a theory in search of facts; that is, some folks start with the theory that SSA is genetic and work backwards. Women who mate with SSA men, it is suggested, are more fecund: they pump out more babies. What we have is a balancing act. Is it because the women who “go for” SSA men are more fertile, or is it the male gametes from SSA men are causing greater fecundity? And how much more fertile must these women be (by whatever cause) to match the rate of baby making seen in women who mate with non-SSA men?

That would seem to be (to reuse the apt word) considerable, especially these days when SSA behavior is seen as socially acceptable. SSA men aren’t making many babies. True, many SSA men in the past days were encouraged to take a wife and reproduce. Not so now. Yet SSA is on the rise. Another paradox—but only if you insist the heritability theory is (somehow) correct. There is no paradox if the diseugenic SSA trait is caused by environmental stressors. I have some colleagues who suspect SSA is caused by a yet-to-be-discovered virus. I doubt this strongly, because it seems that genetic non-immunity to this virus would also die out of the population (the virus could mutate, of course).

The environmental hypothesis, incidentally, also has going for it that in LGBT we have all kinds of other behaviors besides strict SSA. There are far more “B”S than “G”s, for instance. And nobody knows much about the genetic facets of “L”s. “T”s are surely just plain mentally ill.

What impressed me about this study was its coverage. Kelly Servick at Science Mag said of the methods used by Sander “the genetic linkage technique has largely been replaced with genome-wide association (GWA) studies.” She reported that the editor of the journal was surprised to see the study because it used such a blunt instrument, and she said, “Sanders admits that although the strongest linkage he identified on chromosome 8, using an isolated genetic marker, clears the threshold for significance, the Xq28 linkage does not.”

Also consider we do not know how pairs of non-SSA men would look on these same techniques. If these siblings also show similar patterns on chromosome 8, then we’re looking at something similar to brothers, not just to SSA status.

Lastly, Samantha Allen at The Daily Beast note (correctly) that SSA can be a choice.

Update I stupidly forgot to point to Robert Reilly’s and to Stephen Goldberg’s books which correctly point to the evidence that the rate of SSA in identical twins is far from 100%, thus proving the genetic component, if any, cannot be all important.

Upcoming Probability & Statistics Talks! The Climate, Over-Certainty & More!

lecturer

Update Classic Posts page link fixed.

When & Where

I have no idea. As soon as somebody hires me to give them.

Since I am out of the system, I don’t know anybody and thus can’t ask the right personages, whomever they may be, so I’m asking you, dear readers, on the wee small chance you might be the right person.

Titles of some talks:

  • The Over-Certainty Pandemic,
  • Science, Not Scientism,
  • Everything You Believe About Statistics is Wrong,
  • Top Seven Fallacies in Probability and Statistics,
  • What Predictive Analytics Should Be,
  • Global Warming Isn’t So Hot.

Custom talks, seminars, classes and so forth made on request. See the Classic Posts page for sample videos.

Blog Changes: Classic Posts

Following some good advice from our friend John Cook, I did some tweaking on the layout. Of most interest is the fixing of the Classic Posts page, which is now linked on the right sidebar.

Navigation is easier, and after I winnow some of the older material on statistics, it will be easier still.

The Contact Me page has the old Hire Me and Talks page and also information about subscribing to the blog. See the Contribute page about contributing guest posts. Any regular reader is a colleague.

I’ve also cleaned up the Who is WMB page. Pay special attention to the words “I am wholly independent; i.e., I have no position. I depend on you, dear reader, for my livelihood. I do not jest. Spread the word.”

Be careful who you spread it to. I was lined up at a major you-know-the-name think tank for a position on exposing the statistical errors in global warming, but it turned out upon vetting, so I was point-blank told, that a VP at the fine organization was himself same-sex attracted and took wild exception to my position on so-called same-sex marriage. So my job was called off.

What have the two things, global warming and the philosophy of natural law, to do with one another? “Nothing” is the answer I’m looking for. But politics is politics.

This reminds me of the best advice I can give new academics: keep your mouth shut and toe the line until you get tenure. But by then, of course, it might be too late.

Update For climate fans, it seems appropriate here to re-present the running total of all consideration I have received for my work on global warming: $0 (rounded to the nearest dollar). I only wish the conspiracy fans were right about Big Oil passing out money like the government does grants to true believers.

Time Series

I’ve been asked by people via email about where folks can go to read more about Time Series, particularly those new and shiny methods written about it “Netherlands Temperature Controversy: Or, Yet Again, How Not To Do Time Series“. Here.

And in my upcoming book—to be published by…?

I am the only one I know who writes about these things. All statistics books I know are interested, as is natural, in discussing zippy keen methods and not the philosophy. Not only with time series, but with all sorts of analyses. It’s not that the philosophy is entirely neglected, but it’s a poor cousin next to the mathematics.

Incidentally, I was very proud of us with that post. Many people, whether the agree or disagree, are finally starting to understand what I’m saying. If you understood that post, then you’ll finally get this one: “The True Meaning Of Statistical Models.” I’ll redo this one (yet again) maybe tomorrow or Monday. Not repost, redo. There’s always another way to state things.

What Book?

It’s being worked on, slowly and surely. A well known publisher is considering it. If they reject it, which is likely on the premise that most publishers reject most manuscripts, I’ll try with another, then another, then back to self publishing. I’ll comfort myself with the memory that Principia Mathematica was also self published.

On the other hand, the PM, though it was influential, wasn’t read! (I dare you to try.)

Always End With A Joke

Briggs: Jimmy, where are you going tomorrow?

Durante: I’m goin’ to the insane asylum.

Briggs: An insane asylym?

Durante: Yeah, I’m gonna get me a ravin’ beauty.

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