Quote:
Originally Posted by Ryan_Todd
I don't care to dredge up enough memories of my statistics courses...
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I'll do the statistics!
First off, we have to assume that the responses were a random sample of ChiefDelphi users. In reality, they almost certainly weren't--this was a voluntary response survey, which are usually terrible at imitating randomness (for example, maybe non-US members would be more inclined to answer because they want to represent their country). But for the sake of calculations, we'll pretend that it is.
The
FRC 2015 season facts flyer says that 87.2% of FRC teams last year were in the US. To use this as our percentage of ChiefDelphi members who theoretically would live in the US, we need to assume that there is no difference in the average team size between the US and the rest of the world, all ChiefDelphi members are FRC members
, and the percentage of teams in the US hasn't changed since last year.
Assuming all of the above are true or negligible: if ChiefDelphi members' nationalities represented FIRST as a whole and the true proportion of ChiefDelphi members who are from the US is 87.2%, then the likelihood that 79.8% or less of 119 respondents would have been from the US is only 0.8%. This is very strong evidence that ChiefDelphi members are disproportionately from outside of the US.
Again assuming all of the above stipulations, we can be 95% confident that the true proportion of ChiefDelphi members who are from the US is between 72.6% and 87.0%. Whether this is a large enough difference to matter in strategy discussions, I can't say.