Friday, 29 November 2013

Binomial Probability

In 2011, Donald Smith from Victoria University asked me a question about computing gambling outcomes using Mathematica. I generated a CDF examining three cases.

Probability of correctly selecting 1 from m from n goes, with vertical lines at the expected average, and the break-even line when paying odds of p:1:

For larger samples the abscissa indicates percentages, which keeps the average and break-even lines in the same place for comparison purposes:

Use RandomVariate to randomly select 10k samples from BinomialDistribution, plotting the results and expected results onto percentage abscissa:

Friday, 15 November 2013

The problem with P-values

Valen Johnson has been getting a lot of press this year for his paper Revised standards for statistical evidence. It was highlighted in Nature as Weak statistical standards implicated in scientific irreproducibility, on the ABC as Stringent statistics make better science, and mentioned (twice) in The Australian: Pharmas 'concerned' at low evidentiary bar.

The paper is well-written, and the mathematical appendix clear and useful. However, my initial reading of the paper indicates that some useful prior work was not cited. In particular, I first became aware of the problem with P-values through the writings of Robert Matthews. His 1998 paper Facts versus Factions: The use and abuse of subjectivity in scientific research—which was published in 2000 in Rethinking Risk and the Precautionary Principle (pages 247-282)—cites Pocock and Spiegelhalter (1992), which is also cited in Bayesian Methods in Clinical Trials by Deborah Ashby (2005).

Facts versus Factions addresses some of the same topics as Johnson and also has a mathematical appendix, which I re-worked as a Mathematica Notebook here. There is also a Bayesian Credibility Analysis online calculator, and a nice overview of this topic in Matthews' Bayesian Critique of Statistics in Health: The Great Health Hoax.

Updates: Nature has just published a very readable news feature by Regina Nuzzo entitled P values, the 'gold standard' of statistical validity, are not as reliable as many scientists assume.

And my colleague Ron Monson has collected a number of groaning puns that are defining a new growth industry:
  • The problem with p values: how significant are they, really?
  • The Earth is round p<0
  • Give p a chance: significance testing is misunderstood
  • Friends don’t let friends calculate p-values
  • A Dirty Dozen: Twelve P-Value Misconceptions
  • The road to NHST is paved with good intentions
  • On The Surprising Longevity Of Flogged Horses: Why There Is a Case for the Significance Test
  • Replicability in Psychological Science: A Crisis of Confidence?
  • To P or not to P: on the evidential nature of P-values and their place in scientific inference
And  finally, if you worked at a particular UK university this one might have come across your desk as a research proposal (sadly for the academy though, I don't think it ever did make it to a thesis or publication stage):
  • Ménage à Trois Inference Style: Unifying Three Hypothesis Testing Doctrines
As much as one wants to defend the scientific method against pseudo-science, modern medicine is smug in its superiority over chiropractory and alternative medicine, but it is sobering that all medical research is based on using p values as the "gold standard".

Sunday, 6 October 2013

Rogue bankers, cyber crims have hijacked maths

Edited version of Hannah Devlin's column in The Times (reprinted in The Australian):

Mathematics has lost its moral purity as it is open to misuse by bankers and rogue regimes. Andrew Wiles said his subject had become a powerful tool that could be used for financial gain and as a weapon in cyberwarfare. In the past century, physicists worried about the ethical implications of their work, while mathematics was one step removed from life's gritty realities. "It's not true anymore," Wiles said. "The diversion of one's research towards goals that you might not believe in—that's happened to mathematics now."

Wiles was marking the opening of the Mathematical Institute in a building named after him. The institute features Penrose tiling and crystal-like canopies and windows, aimed at demonstrating how mathematical ideas are part of everyday life. Sam Howison said the new building would bring together those working on abstract mathematics and those working on more applied problems, including the mathematics of whips, knots, jet engines and DNA.

Wiles, who returned to Oxford from the US in 2011, said the role of mathematics in the global financial crisis—in particular the misuse of complex derivatives by banks—had sullied the reputation of his subject by association. In theory, good risk analysis and statistics ought to have averted a financial crisis, he said, but poor communication between mathematicians and those who employed them meant the limitations of predictive algorithms were not fully appreciated. In future, he said, society needed to become better equipped to make sense of issues such as cyber security and internet privacy, which relied on encryption algorithms. "Mathematics is just the language in which the quantitative world is written, and the world is becoming far more quantitative," he said. "People have to be more conscious of the pitfalls of errors and statistics and the limits of security."

Parents and teachers should expose children to the great unsolved problems of mathematics as well as the textbook rules of algebra. He said there was a popular misconception that his success was mostly down to his being a mathematical genius. "The thing about mathematics that people don't realise is that research really involves wasting time," he said. "It's not that you're just so clever that you immediately go down the right path. "On the contrary, it's really about persistence and dealing with the setbacks." 

Wiles is now focused on proving the Birch and Swinnerton-Dyer conjecture, one of the seven Millennium Problems, for which a correct solution carries a $US1 million prize.

In the footsteps of Frank Lloyd Wright

In the Footsteps of Frank Lloyd Wright, an architecture tour of the USA, was recently advertised in The Weekend Australian. As a big fan of FLW, I've visited the Robie House, Oak Park:
the Guggenheim Museum, Kentuck Knob:
and Falling Water:

Monday, 2 September 2013

Coffee in NYC

New Yorkers finally warm to the humble Aussie flat white mentions a number of Australian-owned cafes, which are changing the way New Yorkers drink coffee (see also Good Coffee in NYC):
  • Toby's Estate in Williamsburg (125 N 6TH St, Brooklyn)
  • Grumpy's has cafes in two Brooklyn neighbourhoods
  • Bluebird in the East Village
  • Laughing Man in TriBeCa is co-owned by Hugh Jackman
  • Milk Bar (620 Vanderbilt Ave, Brooklyn)
  • Smooch (264 Carlton Ave, Brooklyn)
  • Pie Face (with Australian site here), has 5 outlets in NYC. According to marketing manager Tennille Scicluna, "Only when you venture abroad do you realise how advanced our coffee culture in Australia truly is"
According to Caroline Jumpertz, NYC coffee culture has "seriously ramped up" with US roasters:
Interestingly, one reason for the Australian-owned cafes is the relative ease of acquiring an E-3 visa—available since the free trade agreement between Howard and Bush—as a lure to entrepreneurs to open small businesses.

Sunday, 23 June 2013

Secular curriculum?

In PM's school reform flawed Kevin Donnelly writes
The curriculum states that Australia is "a secular nation with a multicultural and multi-faith society"; one where students are told they should "learn to value their own cultures, languages and beliefs, and those of others". Yet, while it is true that Australia is a secular society, ours is predominantly a Christian country and Judeo-Christian values are the bedrock of our institutions and way of life. Tolerance, respect for others, equality before the law, individual liberty, honesty and truth telling are values that define us as a nation and they can only be fully understood in the context of the Christian religion.
Absolute nonsense! Only someone indoctrinated in Christianity—and I strongly suspect Catholocism—would hold that view. Humanists and atheists would reject this position unequivocally. He adds
Mandating a cultural Left national curriculum on schools will leave students with a biased understanding of their responsibilities as citizens.
Really? Perhaps it would introduce more balance, or a counter-balance, to the religious and Right bias of The Australian.

While Donnelly declares that he is
...director of Education Standards Institute and author of Educating Your Child: It's not rocket science.
he does not declare his religious affiliation. Surely full disclosure is required here!

When I was looking for this article on the web I came across Literacy—Why I reject Kevin Donnelly’s educational analysis, which I found most interesting. It seems that Donnelly's regular column in The Australian—like that of many other columnists—is due, at least in part, to a worldview mirroring that of the newspaper.

Friday, 21 June 2013

Silly cheque

I kept this 2007 cheque from Alinta because it cost at least 3 times as much to post the cheque to me!

Monday, 17 June 2013

Hedy Lamarr: Not just a pretty face ...

Following up on a tumblr post, led me to a Guardian article. Eventually, I found more detail about Hedy Lamarr's patent application for a "Secret Communication System" as From Strapless to Wireless. Most interesting stuff ...

Wednesday, 5 June 2013

Crispian Jago is behind The Reason Stick blog. Some favourites:

Wednesday, 22 May 2013

Margaret River Architecture

Apart from kit houses, there is some really nice architecture in Margaret River. Some of the work by Sorenson Architects, theo mathew, and nikko design is very special.

Kit houses

I'd never been a fan of kit houses until I saw a house for sale in Margaret River built by bachkit.

Now that some local councils are permitting building separate rental accommodation (of up to 70sqm) some nice, affordable, innovative solutions are appearing. Blue Frontier has pods and studios (also suitable for weekenders), with architecture by Robert Andary.

Monday, 6 May 2013

Dumb cuts

In response to the federal government announcement that university funding would be cut by $2.3 billion, Jeannie Rea from the National Tertiary Education Union (NTEU) wrote to members on April 15 as follows:
While the NTEU welcomes the school education reforms, this should not come at the cost of public investment in universities and support for higher education students. The announcement of a $900 million direct cut to university funding is a further blow to universities who have copped cuts each time the Government has sought to make budget savings.
As a member of the NTEU it is hard to disagree with that. The dumbcuts website encourages members to email the Prime Minister Julia Gillard and Education Minister Craig Emerson expressing opposition to the funding cuts, and requests that members
...send us any feedback you have about the funding cuts and NTEU's response. We will continue to develop and update the campaign web site over the coming weeks.
I replied to Jeannie as follows:
It must be clear to everyone, especially after this announcement, that the Labor party will not be re-elected when the election is held later this year. So spending time and effort to get them to reverse these cuts, which will not apply until 2014, is likely to be a waste of time and effort. 
What is most important instead is for the NTEU to obtain a commitment now from the Liberal party that they will reverse these cuts. I expect that, instead, the Liberals will say that they will not commit to reversing the cuts upon gaining power until the full state of the budget is known. 
Such a response would be unacceptable, so all possible powers of persuasion—from the NTEU and Universities Australia—should be put to bear on the Liberals to secure reversal of the cuts as a core election promise.
So far I have received no response from Jeannie or the NTEU.

On April 30, in a speech on innovation and research at Monash University, the Opposition education spokesman, Christopher Pyne, warned that the sector would potentially struggle to maintain quality provision. But he gave no sign that the opposition in government would do anything to reverse the cuts. As reported in Pyne sitting on spending cut fence, he signalled that
...the Coalition would seek to cut bureaucracy, and that research funding should be "commensurate" with its importance to the economy. 
and that cutting the deficit remained the priority:
Providing more money for research is something that is much easier to do when the budget is in surplus and the nation's net public debt has been paid off.
On May 1, An open letter to the Prime Minister from Australian Professors and Associate Professors, protesting at the cuts appeared as a full page newspaper advertisement in The Australian and 18 metropolitan and regional newspapers. Unfortunately, I think this advertisement also misses the point; it really should be addressed to the Liberal party.

On May 6, in an update to members, the NTEU wrote:
As the already announced September 14 election approaches, we need to make the quality and funding of Australian universities a visible public issue. The Labor Government is assuming that university staff will not speak up about its cuts because the university funding policies of any future Coalition government are likely to be worse. Labor needs to know that the support of university staff cannot be taken for granted.
I don't follow this. Just because Universities fear what the Coalition will do—and Pyne has already given an indication of that—does not mean they will not speak up. However, the problem is this; Academics now have no real choice when voting in September. A vote for Labor would mean funding cuts to universities, and vote for the Liberals would mean a (likely bigger) funding cut. But in either scenario, the focus should be on Abbott and Pyne, not Gillard and Emerson.
We are demanding that politicians act to reverse Labor’s latest cuts when the Federal Budget Bills are considered in the Parliament later in June.
Good luck with that. Labor has proposed cuts, which the Liberals support, so where will the pressure on either party come from? Labor may think that the School funding, diverted from universities, will boost its support in some sectors, but I expect that it will do little to change the election outcome, which will be a wipe-out for Labor.

Disclosure: the author is an employee of UWA, and the views expressed are those of the author and not those of the University.

Good Coffee in Perth

Adrian Petersen, a second year student in my Electromagnetism course, is also a barrista at Small Print in the CBD. Adrian, noticing my Seven Seeds T-shirt, sent me the following recommendations for good coffee in Perth:
  • Elixir, Nedlands
  • Standing Room Only, Piccadily Arcade. No seats, no food, just coffee. The owner uses a house blend from 5 Senses and gets a guest blend from various roasters each week
  • Eponymous Gordon Street Garage, West Perth, roast their own coffee
  • Eponymous Howard Street has 3 "hole in the wall" cafes, all under the banner of "ristretto coffee roasters"
  • Chalky's, in Fremantle near the Roundhouse. Have the Reuben sandwich if you go here!
  • Maven Espresso, in Raine square in the city. They use Seven Seeds coffee and 5 Senses, but only do muffins, etc.
  • There are also a whole bunch of 5 Senses cafes that are ok, like Hush in Fremantle or Bench in the CBD (who have Belgian couverture chocolate). 
I'd already seen a good review of Gordon Street Garage and another of Typika (from the founder of Cimbalino), both of which I must try out soon.

Wednesday, 1 May 2013

Equal rights for women?

Two quotes from Campus 'leaping back to dark age', about an Islamic public event held at Melbourne University. Tony Abbott said that
I find that absolutely extraordinary that a great liberal institution would take a huge leap back into the dark ages.
Minister for the Status of Women, Julie Collins, said
Custom, tradition or religious consideration should be no reason to deny women equal rights. The Australian government is working hard to remove all barriers to women's full and equal participation in the workplace, in the community and in civic and political life.
Suppose instead that it was a Catholic event. The Catholic church does not permit women the right to be a Priest (see Why are women not allowed to become priests?). So, is Tony Abbott implying that his church is still in the dark ages? I assume then that the Australian government is working equally hard towards addressing this denial of women's rights—but I won't hold my breath.

Disclosure: the author is an employee of the University, and the views expressed are those of the author and not those of the University.

Monday, 22 April 2013

Universal asymmetry

The news item Planck telescope peers into primordial Universe states:
Planck also confirmed some oddities earlier picked up by the WMAP. The simplest models of inflation predict that fluctuations in the cosmic microwave background should look the same all over the sky. But the WMAP found, and Planck has now confirmed, an asymmetry between opposite hemispheres of the sky, as well as a ‘cold spot’ that covers a large area
The asymmetry “defines a preferred direction in space, which is an extremely strange result”, says Efstathiou. This rules out some models of inflation, but does not undermine the idea itself, he adds. It does, however, raise tantalizing hints that there may yet be new physics to be discovered in Planck’s data.
Figure 1 from Webb and Flambaum's paper Indications of a Spatial Variation of the Fine Structure Constant shows the relationship between the spatial dipole variation in α and the cosmic microwave background dipole and antipole.

What would be most interesting is a variation in the speed of light—or other fundamental physical constants—that shows similar variation.

Saturday, 6 April 2013

Architect’s grand design gets nod

The April 6 POST highlighted architect Ariane Prevost’s proposed house at 3A Queen Street Claremont and mentioned that it could feature on Grand Designs Australia. Her name sounded familiar—and then I remembered: when I started at UWA in 1978, in my first year I studied Architecture, along with Physics and Maths. And the top student in Architecture was Ariane Prevost.

A search revealed that her wonderful Marimekko house—featured on Dream Build—was selected as a finalist for the 2012 Houses Awards.

Monday, 18 March 2013

Cricket chaos theory

Read this paragraph by Peter Lalor and then guess what the article is about
EDWARD Lorenz, one of the fathers of chaos theory, discovered that small changes in initial conditions produced large changes in long-term outcomes. A shortcut in the data entry on a primitive computer created a wildly different conclusion to the one it should have.
Cricket of course! Here's the next paragraph:
Shortcuts have got Australian cricket here—climbing out of a car wreck on a dusty Indian back road.
You have to love a writer who can put cricket and chaos together so elegantly...

Thursday, 28 February 2013

AFL Full Membership Waitlist

The AFL membership FAQ outlines how AFL Silver Members are automatically placed on the Full Membership waiting list and that, once Full Member upgrades are completed in June each year, Silver Members are advised how many members were upgraded to Full Membership.

I have been a Silver AFL member since 2007. Reviewing my AFL correspondence, it is interesting to track my progress towards Full Membership: I was my 7857 on the waitlist in 2011, 4899 in 2013, 3753 in 2014, and 1516 for 2015 (I can find no mention of my waitlist number in 2012).

It would nice if the AFL to made the current waitlist number accessible upon login to The intake of Full Members in June 2013 included Silver Members who first joined in 2005, so there's a good chance I will be offered Full Membership for the 2016 season and—and if I miss out then, surely I must make it in 2017!

Wednesday, 30 January 2013

Commonsense on the inviolacy of the confessional

In his letter to The Australian, Alan Slade (Dover Heights, NSW) elegantly put into words the idea that I too had regarding commonsense on the inviolacy of the confessional:
Cardinal George Pell claims that the confidentiality of the confessional is inviolate. This need not be incompatible with compliance with our secular laws. All that is needed is a minor modification to confessional rules. Priests taking confessions can be instructed to refuse forgiveness/absolution to those who commit a crime as defined by the law of the land in which the church is located. The supplicant, as a devout Catholic, will need to submit to the secular legal system before spiritual forgiveness can be considered.
I did not see any response from Pell or the Catholic Church...

Tuesday, 29 January 2013

Saudi reforms

In Newfound status for Saudi women David Ignatius reported that 30 women would join the kingdom’s Shura Council, highlighting the fact that King Abdullah ignored the Saudi cleric who said it would be “haram” under Islam to name women to the council. Ignatius writes
If Saudi women are deemed worthy of joining the body that advises the king on sensitive matters, it’s harder to justify the many limits on their rights.
I wonder what will be the short-term outcome of this initiative.

What will happen to Steve Keen?

I was both amused and amazed by the University of Western Sydney's approach to handling a problematic staff member, Steve Keen. By referring him to the ICAC for his threat to pass all third-year economics students, I wonder if they will open themselves up to a wider investigation into soft marking, such as that reported by The Australian and in meld magazine.

As is pointed out in the latter report, many Australian institutions accept international students with IELTS scores of Band 6, which is only a medium level of English. And this can lead to pressure for soft marking. As Anna Ko says
If universities do not want to practice soft marking, they should raise their admission standards.
Disclosure: the author is an employee of the University of Western Australia, and the views expressed are those of the author and not those of the University.

Doctoral graduates left chasing dreams

Some interesting comments—the growth in the number of PhDs, from 3900 in 2001 to 6500 in 2011, is notable—but few suprises in Doctoral graduates left chasing dreams.

I agree with Richard Strugnell that Australia is producing too many PhDs, and that
We are training them on the assumption they are going into academia. But the majority won't. We just don't know where they end up.
Zlatko Skrbis says
...a judgment cannot be made about what is an appropriate number of PhDs without an understanding of their career outcomes...
which is reasonable, but the following comment about the federal government failing to fund a longitudinal study of PhD graduates sounds like sour grapes; the federal government fails to support the majority of requests for research money!

In Physics, Australian PhDs interested in getting a position in academia usually take post-doctoral positions, often overseas. Those that do return to academia in Australia are enriched by this tortuous track to tenure.

In each issue of Physics World the once a physicist column makes interesting reading. When students ask me "why should I study physics?" or "how does physics training help in other careers?" the answer can likely be found here.

Disclosure: the author is an employee of the University of Western Australia, and the views expressed are those of the author and not those of the University.