Archive for April 11, 2018

Cardiff to Dublin via Belfast

Posted in Biographical, Cardiff with tags , , , on April 11, 2018 by telescoper

I thought I write a brief post to arising from today’s travel difficulties, really just to make a record of the episode for posterity.

As last Wednesday I got up early this morning (4.30am) to get the 7am FlyBe flight from Cardiff to Dublin, due into Dublin at 8.05am. Having only hand luggage, as usual, I proceeded straight upstairs to the departure area only to find that the screen said the flight was cancelled, and directed passengers intending to travel on it back downstairs to the `Disruption Desk’ .

A long queue had already formed by the time I got there, but I got to the desk fairly quickly. The assistant explained that the cancellation was due to `staff sickness’ (i.e. they were short of a pilot) and the only option on offer was to fly to Belfast whence a bus would be provided to Dublin. The Belfast flight should have left at 6.15am but was being held for passengers to Dublin. I was also given a £5 refreshments voucher.

I thought a moment and then decided to accept this offer. I didn’t have any morning appointments today, but definitely had to get to Maynooth somehow by tomorrow morning as I have a lecture to deliver.

The plane left Cardiff about 7.15am and arrived in Belfast around 8.10am but when I emerged from the arrivals area there was no bus. In fact it took about 45 minutes to arrive, and we didn’t get going until about 8.55am. Many of the passengers were clearly nervous about missing connecting flights in Dublin, including a group of women planning onward travel to the USA, but the trip was fairly uneventful apart from the fact that the toilet was out of commission necessitating a stop so that people could use the facilities in a service station.

I can confirm that there is no visible border between Northern Ireland and the Republic on the road between Belfast and Dublin, although it does change name from A1 to M1 on the way. The distance between Belfast and Dublin by road is about 100 miles and it took just over two hours. I arrived at Terminal 1 of Dublin Airport at 11.05, almost exactly three hours late. I thought that wasn’t too bad a result given the chaos in Cardiff when I left but it was still a frustrating morning. I had to wait until 11.50 for the bus to Maynooth, where I finally arrived about 12.40.

I will of course be submitting a request for the compensation to which I am entitled for the delay, but above all I hope that those whose arrangements were even more seriously disrupted than mine managed to get to where they needed to go in the end.

What happens if you ask people to pick a number `at random’ between 1 and 100?

Posted in Bad Statistics with tags on April 11, 2018 by telescoper

I saw this circulating on Twitter and thought I would share it here; it was originally posted on reddit.

The graph shows the results obtained when 6750 people were asked to pick an integer `at random’ between 1 and 100. You might naively expect the histogram to be flat (give or take some Poisson errors), consistent with each number having the same probability of being picked, but there are clearly some numbers that are more likely to be chosen than a constant probability would imply. The most popular picks are in fact 69, 77 and 7 (in descending order).

It’s well known amongst purveyors of conjuring tricks and the like that if you ask people to pick a number between 1 and 10, far more people choose 7 than any other number. And I suppose 77 is an extension of that. More interestingly, however, the top result implies that, given the choice, more people seem to prefer a 69 to anything else…

Anyway, it proves a point that I’ve made more than a few times on this blog, namely that people generally have a very poor idea of what randomness is and are particularly bad at making random choices or generating random sequences.

P.S. Please direct any criticism of the graph (e.g. why the x-axis goes up to 104 or why the x-values are given to two decimal places) to the reddit page…