111–120 of 132 posts
Here's a histogram of ages, as they appear right now in the poll. It seems they follow a poisson distribution peaking around 27. ------- --------------------------------------- ------------------------------------ ------------------ -------- ------ ----- - - -
I feel better now.
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Why would you call it poisson?
Because it looks like one (compared to Gaussian it's skewed): http://en.wikipedia.org/wiki/Poisson_distribution
Graph, updated every hour: http://koldfront.dk/misc/hn/age.png (until I kill the cronjob :-))
Cool. What are you using to draw the graph?
Someone better than me at math should say how many votes we need to have a 95% accuracy.
The key issue is being good at statistics, not math. The data can't be relied on to make such an inference because they are not from a random sample of the relevant population. VOLUNTARY RESPONSE POLLS One professor of statistics, who is a co-author of a highly regarded AP statistics textbook, has tried to popularize the phrase that "voluntary response data are worthless" to go along with the phrase "correlation does…
Intesting Anecdote: NDTV 24x7 (something like CNN in India) had extensive polls in the last (2004) election where they predicted a huge victory for the BJP party. They had poll results state-wise and interviews with eminent psephologists and so on, all predicting a resounding victory.
In the end, BJP lost - and quite badly too! Lies, damned lies, and statistics...
I just turned 24 today :D
Earlier quoted context omitted.
The key issue is being good at statistics, not math. The data can't be relied on to make such an inference because they are not from a random sample of the relevant population. VOLUNTARY RESPONSE POLLS One professor of statistics, who is a co-author of a highly regarded AP statistics textbook, has tried to popularize the phrase that "voluntary response data are worthless" to go along with the phrase "correlation does…
This is very interesting - does anyone know just how many of the polls we see on TV or in magazines are voluntary response polls? Should we be ignoring their results? Intesting Anecdote: NDTV 24x7 (something like CNN in India) had extensive polls in the last (2004) election where they predicted a huge victory for the BJP party. They had poll results state-wise and interviews with eminent psephologists and so on, all…
Polls in general interest magazines, especially women's magazines, are usually wholly unreliable for modeling reality. (One thing that happens is the college-age men stuff the supply of replies full of phony responses, especially if the survey is about some salacious topic such as sexual behavior.)
I responded to a telephone call that came to my home phone number from Gallup Poll a few weeks after the United States presidential election. Gallup attempts to proactively call all households in the United States, and to correct for households that refuse to answer its calls. The interviews are quite long, and they ask a lot of demographic questions for stratifying the data gathered. If my caller I.D. box had not said "Gallup Poll," I never would have picked up my phone for a cold call. I got another poll call just this weeked, and many years ago got a call from the Harris Poll. The major polling companies attempt to actively gather random data samples, so what they do is distinguishable from voluntary response. But a magazine that writes a little sidebar "email your response to [email address]" is simply gathering worthless data. The same is true of TV stations that tell viewers to cell-phone text a response to some number they designate, or websites that have a poll form for anyone who surfs by.
If you are gathering data to improve a website, you are much better off conducting a live usability study in which you observe the user directly than simply polling visitors who voluntarily respond.
Graph, updated every hour: http://koldfront.dk/misc/hn/age.png (until I kill the cronjob :-))
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> So, doesn't that just mean that a statistically significant portion of the regular HN users would have to respond? No. If 50% of HN visitors voted but 99% of those over 40 didn't (due to whatever confounding factor you like - say embarrasment), you'd still wouldn't be able to extrapolate from the sample to the category of "HN visitors".
Correct. It doesn't matter how large a sample size is if the sample is biased. This should be something that every high school student knows after any high school statistics course, but it is a crucial consideration that is widely ignored.
eg: a gender survey in the general population that transgender respondees do not answer -- ends up with a 99% sample size (all but the transgenders) -- and thus gives a pretty significant bit of data on male:female ratios, etc..
Agreed in principle though.