I'm been playing with a little app on my phone lately called 'Are You Psychic?' It prompts you to choose one of the five cards shown above on twenty five occasions. Laws of chance predict that a score of five or below is unremarkable. But if you consistently get more than this on subsequent attempts then something else may be going on.
These are Zener Card, produced by a scientist of the same name in the early 1930s for testing ESP. 'Ah they're the cards in the scene in Ghostbusters where Bill Murray was perving!' said Barbie Nurse. There's other sets of cards to choose from in the app but I'm rather partial to these because of their provenance.
So how am I doing? Well my combined test results are at 23%. I've scored 12/25 on a couple of occasions and I often get a run of scores over five. I'm less 'psychic' when I'm a bit stressed or tired. The lack of consistency means that, in spite of my gypsy ancestry, I won't be opening a booth on Brixham Harbour and inviting people to cross my palm with silver any time soon!
What the process has sparked is a latent interest in probability. Maybe this is fascinating me more than the hocus pocus. What I'm trying to work out at the moment is the chance of getting any particular score. I think I've found the formula but my rusty maths head is struggling to use it. I'll post the chances of scoring 12/25, which I thought was pretty impressive, when I've worked it out.