Not really. The data here (if collected more fully, including date of purchase) are valid for any statistical analysis of 360's reliability.
No its not. Sample size is to small, and the sample is not a representative of the average X360 console, the method of acquiring the data (website polling) is also not reliable, all in all, its not worth anything as far as statistical analysis goes.
Even if you collect data more specifically, it would still be invalid for any real statistical use, why? Because people with working consoles are less likely to seek out threads about reliability and less likely to vote. People by nature, like to complain about bad things rather than compliment good things. And again, the sample data being so small, leads to big chance of the data being inaccurate.
My question was: How does B3D's composition affect the failure rate of their 360s ? If it's because B3D posters buy more launch consoles, it just means that we have better/more data for launch consoles.
And i already answered this about 10 times now. Since there is a higher consistency of early adapters, we would get an inflated failure rate. Therefore the data you would collect, would be flawed in terms of any general failure rate conclusions.
The result does not necessarily have to depend on whether the buyers are "representative of the consumer population"
No, but it has to be a representative of the consoles, and it has to be in a big enough sample. Even if we would do as you suggest, and collect the data as date of purchase from the voters, its not good for any real use, because people have to actively seek out this poll in order to vote. And no matter what argument you make, the sample size will still be far to small to even give you an indication of anything, statistically speaking.
437 dead consoles, 14 on life support. 359 individual posters.
I thought il add to this, since you figure that this "official x360 death" topic is such a great piece of source data RolfN, here a little math based on it. Since we do not know the total amount of people with X360's on Neogaf, therefore we have no ways of knowing the actual reliability rate of that population, the only meaningful statistic we could get for reliability would be to look at the reliability of the replacements.
Apparently, 359 people have had 437 dead consoles. Assuming that these broken consoles have been replaced by the warranty, this would mean out of 359 replacement consoles, only 78 consoles died, the rest is working.
76\359 = 21,71% failure rate. So now RolfN, in regards to this:
2. There is not a single sample population that shows failure rates under 30%.
we now have a sample population that do show less than 30% failure rate.
Of course, this data is just as flawed, as all the other data we have been discussing, (yet less flawed than your example that just showed "total" failed consoles on neogaf)