On 16/10/2019 19:52, MRAB wrote: > On 2019-10-16 19:43, duncan smith wrote: >> On 16/10/2019 04:41, DL Neil wrote: >>> On 16/10/19 1:55 PM, duncan smith wrote: >>>> On 15/10/2019 21:36, DL Neil wrote: >>>>> On 16/10/19 12:38 AM, Rhodri James wrote: >>>>>> On 14/10/2019 21:55, DL Neil via Python-list wrote: >>>>> ... >>>>> So, yes, the "label" is unimportant - except to politicians and >>>>> statisticians, who want precise answers from vague collections of >>>>> data... (sigh!) >>>>> >>>> >>>> [snip] >>>> >>>> No not (real) statisticians. People often want us to provide precise >>>> answers, but they don't often get them. >>>> >>>> "It ain’t what you don’t know that gets you into trouble. It’s what you >>>> know for sure that just ain’t so." (Mark Twain - perhaps) >>> >>> +1 >>> >>> Although, you've undoubtedly heard people attempt to make claims of >>> having 'accurate figures' (even, "that came from Stats") when you told >>> them that the limitations and variations rendered the exercise >>> laughable... >>> >>> My favorite (of the moment) is a local computer store who regularly >>> offer such gems as: (underneath the sales (web-) page for an upmarket >>> *desktop* computer) "people who bought this also bought" followed by at >>> least two portable PC carry cases. They must be rather large carry-bags! >>> (along with such surprises as keyboard, mouse, ...) >>> >>> This morning I turned-down a study for a political group. One study has >>> already been completed and presented. The antagonist wanted an A/B >>> comparison (backing his 'side', of course). I mildly suggested that I >>> would do it, if he'd also pay me to do an A/B/C study, where 'C' was a >>> costing - the economic opportunity cost of 'the people' waiting for 'the >>> government' to make a decision - (and delaying that decision by waiting >>> for "study" after "study" - The UK and their (MPs') inability to decide >>> "Brexit" a particularly disastrous illustration of such) >>> >>> >>> Sorry, don't want to incur the anger of the list-gods - such >>> calculations would be performed in Python (of course) >> >> Clearly, all such analyses should be done in Python. Thank God for rpy2, >> otherwise I'd have to write R code. It's bad enough having to read it >> occasionally to figure out what's going on under the hood (I like >> everything about R - except the syntax). >> > I have too many examples of people ignoring random variation, testing >> hypotheses on the data that generated the hypotheses, shifting the >> goalposts, using cum / post hoc ergo propter hoc reasoning, assuming >> monocausality etc. In some areas these things have become almost >> standard practice (and they don't really hinder publication as long as >> they are even moderately well hidden). Of course, it's often about >> policy promotion, and the economic analyses can be just as bad (e.g. >> comparing the negative impacts of a policy on the individual with the >> positive impacts aggregated over a very large population). And if it's >> about policy promotion a press release is inevitable. So we just need to >> survey the news media for specific examples. Unfortunately there's no >> reliable service for telling us what's crap and what isn't. (Go on, >> somebody pay me, all my data processing / re-analysis will be in Python >> ;-).) >> > Even when using Python, you have to be careful: > > Researchers find bug in Python script may have affected hundreds of studies > https://arstechnica.com/information-technology/2019/10/chemists-discover-cross-platform-python-scripts-not-so-cross-platform/ >
Yes, the problem of standing on the shoulders of others (not necessarily giants). I assume the problematic code was tested on an OS that happened to sort the results as required. Years ago I had a similar issue with a race condition, but we caught it because I developed the code under Linux and everybody else on the project ran it under Windows (where the bug surfaced). Note to self: before I do any more parallel programming check out how to test for race conditions. Duncan -- https://mail.python.org/mailman/listinfo/python-list