Age of ukcaving posters

[Roger W]

Just check out how many forum users

a.  prefer ladders to SRT

b.  prefer rope ladders to these new-fangled wire things

c.  swear by candles as a preferred illuminant

d.  advise the use of Harris tweed for caving wear

etc...

 

[kay]

A random selection of 150 profiles of users who have posted over 100 times (ie 3.3% of registered users - not really a statistically significant figure I know)

An interesting topic- glad you started this. But you can't wave a statistic under the nose of a statistician and expect them not to go off on a discourse that will have everyone else dying of boredom ... ;-)

The 3.3% isn't the real problem - contrary to popular belief, it's the size of the sample rather than what proportion it is of the population that governs the confidence you can have in the result - a sample of 150 from a population of 100,000 is as good as a sample of 150 from a population of 1000.

There's more effect from whether your sample is truly random or not. You took a sample from those who've posted over 100 times, so that's clearly not a random sample of registered users, so you can't regard your result as a reliable estimate of the average age of registered users. On the other hand, you may have wanted to look at regular posters only, in which case your "population" was posters of over 100 posts. How reliable your average age is as an estimate of the average age of posters of over 100 posts depends on your sampling technique and the reasons behind the very high number of missing values (eg it may be that older posters are less willing than younger ones to reveal their age on a forum, or vice versa) - and of course you can't then extrapolate to the different population of "all regular users".

 

[2xw]

A random selection of 150 profiles of users who have posted over 100 times (ie 3.3% of registered users - not really a statistically significant figure I know)

An interesting topic- glad you started this. But you can't wave a statistic under the nose of a statistician and expect them not to go off on a discourse that will have everyone else dying of boredom ... ;-)

The 3.3% isn't the real problem - contrary to popular belief, it's the size of the sample rather than what proportion it is of the population that governs the confidence you can have in the result - a sample of 150 from a population of 100,000 is as good as a sample of 150 from a population of 1000.

There's more effect from whether your sample is truly random or not. You took a sample from those who've posted over 100 times, so that's clearly not a random sample of registered users, so you can't regard your result as a reliable estimate of the average age of registered users. On the other hand, you may have wanted to look at regular posters only, in which case your "population" was posters of over 100 posts. How reliable your average age is as an estimate of the average age of posters of over 100 posts depends on your sampling technique and the reasons behind the very high number of missing values (eg it may be that older posters are less willing than younger ones to reveal their age on a forum, or vice versa) - and of course you can't then extrapolate to the different population of "all regular users".

I was thinking of writing something in Rcrawler for this sort of analysis to sample the entire user base when I have spare time (although I'd have to ask Badlad nicely and I suspect they might be able to do this sort of analysis themselves...)

 

[JoshW]

A random selection of 150 profiles of users who have posted over 100 times (ie 3.3% of registered users - not really a statistically significant figure I know)

An interesting topic- glad you started this. But you can't wave a statistic under the nose of a statistician and expect them not to go off on a discourse that will have everyone else dying of boredom ... ;-)

The 3.3% isn't the real problem - contrary to popular belief, it's the size of the sample rather than what proportion it is of the population that governs the confidence you can have in the result - a sample of 150 from a population of 100,000 is as good as a sample of 150 from a population of 1000.

There's more effect from whether your sample is truly random or not. You took a sample from those who've posted over 100 times, so that's clearly not a random sample of registered users, so you can't regard your result as a reliable estimate of the average age of registered users. On the other hand, you may have wanted to look at regular posters only, in which case your "population" was posters of over 100 posts. How reliable your average age is as an estimate of the average age of posters of over 100 posts depends on your sampling technique and the reasons behind the very high number of missing values (eg it may be that older posters are less willing than younger ones to reveal their age on a forum, or vice versa) - and of course you can't then extrapolate to the different population of "all regular users".

I was thinking of writing something in Rcrawler for this sort of analysis to sample the entire user base when I have spare time (although I'd have to ask Badlad nicely and I suspect they might be able to do this sort of analysis themselves...)

I think 'regular posters' needs a more airtight definition. I'm sure there are people that have posted regularly 5/6 years ago, got a couple of hundred posts, but never done anything since - are they still a regular poster?

 

[mch]

A random selection of 150 profiles of users who have posted over 100 times (ie 3.3% of registered users - not really a statistically significant figure I know)

An interesting topic- glad you started this. But you can't wave a statistic under the nose of a statistician and expect them not to go off on a discourse that will have everyone else dying of boredom ... ;-)

The 3.3% isn't the real problem - contrary to popular belief, it's the size of the sample rather than what proportion it is of the population that governs the confidence you can have in the result - a sample of 150 from a population of 100,000 is as good as a sample of 150 from a population of 1000.

There's more effect from whether your sample is truly random or not. You took a sample from those who've posted over 100 times, so that's clearly not a random sample of registered users, so you can't regard your result as a reliable estimate of the average age of registered users. On the other hand, you may have wanted to look at regular posters only, in which case your "population" was posters of over 100 posts. How reliable your average age is as an estimate of the average age of posters of over 100 posts depends on your sampling technique and the reasons behind the very high number of missing values (eg it may be that older posters are less willing than younger ones to reveal their age on a forum, or vice versa) - and of course you can't then extrapolate to the different population of "all regular users".

Many thanks kay for your comments. When I started this thread I didn't really expect much of a response so I didn't go into my "methodology" (doesn't really deserve such a description!) in any great depth. If you look at the list of members there are large numbers (I haven't counted them so it's just a subjective observation) who have never posted. I had a look at a random dozen such members and none had filled in age, location or gender so I figured (again subjectively) that this was probably true of most nil posters and that would skew the results if I included them. If people had troubled to post over 100 times then it was likely that they had a genuine interest in the forum (either now or in the past) and the results may (or may not!) be more meaningful.

I have to say that the exercise wasn't intended to be scientific or to produce results from which deductions could be made. I just did it for my own interest and then thought that I should share it on the forum. Pleased that it has attracted comment.

 

[teabag]

I've made us a poll. Obviously it is self-selecting and we won't know if you've told the truth. But it doesn't give your name so you can tell us anonymously and you don't have to post in the forum to take part (other than this once!) - I didn't post for ages after I joined but I visited at least once a week as there was always something of interest, so I thought it would be good to include all 'users'.

 

[mch]

I've made us a poll.

Nice one teabag!  It will be interesting to see how many of the 4,000+ users respond.