The Problem Of Grue Isn't

The so-called problem of grue was introduced by Nelson Goodman in 1954 as a "riddle" about induction, a riddle which has been widely thought to cast doubt on the validity and rationality of induction. That unnecessary doubt in turn is partly responsible for the reluctance to adopt the view that probability is part of logic. Several authors have pointed out deficiencies in grue; nevertheless, the "problem" still excites. Here, adapted from Groarke, is presented the basis of grue, along with another simple demonstration that the "problem" makes no sense and is brought about by a misunderstanding of causation

Broccoli Reduces The Risk of Splenetic Fever! The use of induction and falsifiability in statistics and model selection

The title, a headline, and a typical one, from a newspaper's "Health & Wellness" section, usually written by a reporter who has just read a medical journal, can only be the result of an inductive argument, which is an argument from known contingent premisses to the unknown. What are the premisses and what is unknown for this headline and what does it mean to statistics? The importance--and rationality--of inductive arguments and their relation to the frequently invoked, but widely and poorly misunderstood, notion of `falsifiability' are explained in the context of statistical model selection. No probability model can be falsified, and no hope for model buidling should be sought in that concept.Comment: 20 page

The Third Way Of Probability & Statistics: Beyond Testing and Estimation To Importance, Relevance, and Skill

There is a third way of implementing probability models and practicing. This is to answer questions put in terms of observables. This eliminates frequentist hypothesis testing and Bayes factors and it also eliminates parameter estimation. The Third Way is the logical probability approach, which is to make statements $\Pr(Y \in y | X,D,M)$ about observables of interest $Y$ taking values $y$, given probative data $X$, past observations (when present) $D$ and some model (possibly deduced) $M$. Significance and the false idea that probability models show causality are no more, and in their place are importance and relevance. Models are built keeping on information that is relevant and important to a decision maker (and not a statistician). All models are stated in publicly verifiable fashion, as predictions. All models must undergo a verification process before any trust is put into them.Comment: 14 pages, 4 figure

The Crisis Of Evidence: Why Probability And Statistics Cannot Discover Cause

Probability models are only useful at explaining the uncertainty of what we do not know, and should never be used to say what we already know. Probability and statistical models are useless at discerning cause. Classical statistical procedures, in both their frequentist and Bayesian implementations are, falsely imply they can speak about cause. No hypothesis test, or Bayes factor, should ever be used again. Even assuming we know the cause or partial cause for some set of observations, reporting via relative risk exagerates the certainty we have in the future, often by a lot. This over-certainty is made much worse when parametetric and not predictive methods are used. Unfortunately, predictive methods are rarely used; and even when they are, cause must still be an assumption, meaning (again) certainty in our scientific pronouncements is too high.Comment: Corrected typos; 22 pages, 5 figure

On the non-arbitrary assignment of equi-probable priors

How to form priors that do not seem artificial or arbitrary is a central question in Bayesian statistics. The case of forming a prior on the truth of a proposition for which there is no evidence, and the definte evidence that the event can happen in a finite set of ways, is detailed. The truth of a propostion of this kind is frequently assigned a prior of 0.5 via arguments of ignorance, randomness, the Principle of Indiffernce, the Principal Principal, or by other methods. These are all shown to be flawed. The statistical syllogism introduced by Williams in 1947 is shown to fix the problems that the other arguments have. An example in the context of model selection is given.Comment: 23 page

On Probability Leakage

The probability leakage of model M with respect to evidence E is defined. Probability leakage is a kind of model error. It occurs when M implies that events $y$, which are impossible given E, have positive probability. Leakage does not imply model falsification. Models with probability leakage cannot be calibrated empirically. Regression models, which are ubiquitous in statistical practice, often evince probability leakage.Comment: 1 figur

It is Time to Stop Teaching Frequentism to Non-statisticians

We should cease teaching frequentist statistics to undergraduates and switch to Bayes. Doing so will reduce the amount of confusion and over-certainty rife among users of statistics

MCMC Inference for a Model with Sampling Bias: An Illustration using SAGE data

This paper explores Bayesian inference for a biased sampling model in situations where the population of interest cannot be sampled directly, but rather through an indirect and inherently biased method. Observations are viewed as being the result of a multinomial sampling process from a tagged population which is, in turn, a biased sample from the original population of interest. This paper presents several Gibbs Sampling techniques to estimate the joint posterior distribution of the original population based on the observed counts of the tagged population. These algorithms efficiently sample from the joint posterior distribution of a very large multinomial parameter vector. Samples from this method can be used to generate both joint and marginal posterior inferences. We also present an iterative optimization procedure based upon the conditional distributions of the Gibbs Sampler which directly computes the mode of the posterior distribution. To illustrate our approach, we apply it to a tagged population of messanger RNAs (mRNA) generated using a common high-throughput technique, Serial Analysis of Gene Expression (SAGE). Inferences for the mRNA expression levels in the yeast Saccharomyces cerevisiae are reported

Uncertainty in the MAN Data Calibration & Trend Estimates

We investigate trend identification in the LML and MAN atmospheric ammonia data. The signals are mixed in the LML data, with just as many positive, negative, and no trends found. The start date for trend identification is crucial, with the trends claimed changing sign and significance depending on the start date. The MAN data is calibrated to the LML data. This calibration introduces uncertainty never heretofore accounted for in any downstream analysis, such as identifying trends. We introduce a method to do this, and find that the number of trends identified in the MAN data drop by about 50%. The missing data at MAN stations is also imputed; we show that this imputation again changes the number of trends identified, with more positive and fewer significant trends claimed. The sign and significance of the trends identified in the MAN data change with the introduction of the calibration and then again with the imputation. The conclusion is that great over-certainty exists in current methods of trend identification.Comment: 32 pages, 12 figure

Fixes to the Ryden & McNeil Ammonia Flux Model

We propose two simple fixes to the Ryden and McNeil ammonia flux model. These are necessary to prevent estimates from becoming unphysical, which very often happens and which has not yet been noted in the literature. The first fix is to constrain the limits of certain of the model's parameters; without this limit, estimates from the model are seen to produce absurd values. The second is to estimate a point at which additional contributions of atmospheric ammonia are not part of a planned expert but are the result of natural background levels. These two fixes produce results that are everywhere physical. Some experiment types, such as surface broadcast, are not well cast in the Ryden and McNeil scheme, and lead to over-estimates of atmospheric ammonia