As a matter of principle i don't like linking to my blog, but I am not sure if i can post all the charts here, so here it is - http://jerome23.wordpress.com/2013/01/2 ... ed-houses/

If anyone has experience with logistic curves I have the data in EXCEL and really could do with a hand on that aspect just texting if the relationship is significant between observed and expected values in line with Houran and Lange's hypothesis. From a visual viewpoint I suspect not, but I'd like ot check the mathematics. Anyone able to help?

j x

Isn't this effectively just another form of the phenomenon that has so many names I no longer know which is the most acceptable version...

The same thing as buying a blue BMW and then seeing lots of blue BMW's - a selection bias, synchronicity, whatever the bloody correct psychological term is...


[youtube]http://www.youtube.com/watch?v=S5OQMoSCrqw[/youtube]

Yes absolutely! I agree on the problem naming it. And as to synchronity, when I started looking for the 23's I found them everywhere (I was born on at 5:23 (5=2+3) on 23/08/69 -- 8 is 2 to the power of 3, and of course 69 is 3 x 23. Seriously though, can you see why they predict a logistic curve in their hypothesis? I simply don't get it...

j x

Our brains work through pattern recognition, so we are apt to find patterns and read more into them than they deserve. For example, have a look at "someone"'s "unbelieveable mathematics" thread

You can fit any curve to any data. The trick is in justifying why it is a good idea.

Yep agreed VK. This is what I don't get. I can't see why their hypothesis arose, and why they suggest a logistic curve. If anything it rather suggests backwards hypothesis formation: however I'm pretty certain they had a reason, I just don't understand the logic behind the maths in any way.

j x

jerome wrote:Yep agreed VK. This is what I don't get. I can't see why their hypothesis arose, and why they suggest a logistic curve. If anything it rather suggests backwards hypothesis formation: however I'm pretty certain they had a reason, I just don't understand the logic behind the maths in any way.

j x

I don't have access to their paper so I am going by what you quote on your blog.
The logistic curve follows straightforward from the assumptions given. That's textbook stuff.
I can't say whether the assumptions are in any way justifiable but I have read on social psychology in the wake of the Bem debacle. "Backwards hypothesis formation" is normal practice in that field. If it looks like that, then that's probably the case.

I don't think you can do a significance test on that data. For that you'd have to calculate a probability.
The curve does not tell you anything about probabilities. When you fit the curve you can calculate a standard error from the residuals which you could use for that purpose. But I don't think you are justified in assuming the same SE for all diaries.
There are a couple ways to measure goodness-of-fit or to validate curves in other ways but no real tests as such. Different data sets have different errors and different confounders.

But I don't really know much about time series analysis. You'd probably want an econometrician for an authoritative answer on what you can do in such a situation.

Yeah they are not looking at probability, sorry that's my clumsiness in explaining it. They are looking at the deviation from the predicted logistic curve. That I can understand.

What I don't get is why they decided to make the assumptions they did. That is the weird bit - their hypothesis. I can explain why they got a logistic curve in their actual study - the participants were told to report "equipment behaving erratically" and "even if they believed they knew the likely cause" -- and as we have discovered from the wrongly referenced Wiseman cite in this article http://www.csicop.org/si/show/the_haunted_brain/ the malfunctioning object which makes out up 16 out of 22 phenomena recorded was the phone. So if we assume the phone company fixed the phone around day 15, then the logistic curve follows.

Incidentally for those other than VK, if you are wondering what we are on about, and can not be bothered to read my replication, it's of a paper cited (incorrectly) in this much more readable Skeptical Inquirer article. http://www.csicop.org/si/show/the_haunted_brain/