Wednesday, July 16, 2008

Averages

I've heard that if you have a bunch of people guess how many jelly beans are in a bowl the average of everyone's guesses is much closer than almost everyone's individual guess. The comments on the last post are an interesting demonstration of this principal (although, it doesn't really count as evidence for a bunch of reasons).

I wasn't going to go through it all, but the people have asked so here it is. If you just look at regular readers, I think there are 7 regular readers (engaged readers plus parents and person who has news in the last three months I'm more jealous of than engagement). 4 of those 7 regular readers got engaged in the last three months.

But I was making a statistical comment about that particular post. By mentioning the engaged couples I imagine that I increased the odds that one of them would read it (and by calling her out all but by name in this post I think this even further increases the odds that her finance will encourage to read the post). At this point I think it is a bit better than 50-50 so let's give her a 75% chance and say there are 4.75 people who would have passed the criteria (I'm making a comment on expected value not on the value of the person). I think it is unlikely that the last couple member will read the post (and one of the comments confirms that).

There's one person who I would think reads this, but I really have no idea so since Bayes says with no info it is 50-50 we're up to 3.5 who don't meet the criteria. There's one person who occasional reads this blog, on the high side I'd guess there's a 25% chance of reading any given post so up to 3.75. Then there's 7 family members outside my immediate family who at least know about it and may have read it at some point, but I have a feeling they never or rarely read it at this point, so lets give each of them a 10% chance then we are up to 4.45. I've also had occurrences of random people reading my blog - although there's typically something specific that triggers it. Let's give a random person stopping by an expected value of 0.1 people then we are at 4.55

So we are at 4.75 out of 9.3 which is a 51% chance, but with a fairly wide margin of error. No, I didn't count myself - I guess I should have specified anyone who read it, but didn't write it (although I could claim it was implied by the use of second person).

2 comments:

Anonymous said...

Hmm, I made a bad assumption: I assumed only half of each couple reads the blog. Therefore, for 3 to be greater than half, you'd need only 5. I also assumed that people were wholes, not parts :-P

Second, I can guarantee that the other half of this couple does not (and probably never will) read your blog. He doesn't even read mine!

Third, most blogs have lurkers. I'm willing to bet there are a handful of people out there who read but never comment. I know I have a bunch of those!

The Owl Archimedes said...

Presbyterian for 18 years! But I was reading through my old diary entries a few weeks ago, and apparently I was questioning my faith as early as 9th grade- but in denial about it. As in I wasn't doubting, just "wondering"... Wondering is a dangerous act.

Maybe it's an illusion to think that I understand my mind now, but I feel like my level of self-awareness is higher now than back then. Probably an illusion. A week later, I'll find myself going "what was I thinking??"