Discussion moved from "clarification box" 22:20 Oct 24, 2008
John Peterson: 11:23am Oct 24, 2008: I think I'd stick at "the 95% confidence level if you can". However, terms like "95% certain" are used as well - so that might help. As for being Greek, the symbol for the standard deviation (crudely, a measure of "spread") is the lower case sigma! [Hide] ormiston: 11:27am Oct 24, 2008: am gratefully trying to assimilate all this - but how do I deal with this embellishment?! "écart significatif à 95% entre les hommes et les femmes" [Hide] John Peterson: 11:42am Oct 24, 2008: Maybe say something like: "we can be 95% certain that the difference between men and women is (statistically)significant". - I'd try and keep the "statistically". Or: "There's a 95% certainty that ..." [Hide] B D Finch: 1:42pm Oct 24, 2008: I would disagree with JP's last posting. If one adopts a 95% level of confidence (and the level should be selected before the results are known) then one is saying that the result above that **IS statistically significant** , it might still be wrong. [Hide] B D Finch: 1:47pm Oct 24, 2008: In other words, one can know that something is statistically significant. At a 95% probablity level, that makes it 95% likely to be true, however, it is still 5% probable that it is untrue. Even if untrue, the statistical difference is still significant [Hide] John Peterson: 1:54pm Oct 24, 2008: Re BDF's comment - as we're talking about probabilities, the decision to reject the null hypothesis can be wrong; but the assumption is that a high confidence level reduces the chance of making the wrong decision in terms of rejecting the null hypothesis. [Hide] John Peterson: 2:05pm Oct 24, 2008: The above was a response to BDF's 1st point. Re the second point, statistical significance is about the chance of being right/wrong. The difference may be numerically significant (big/small) but not statistically significant (likely to be right). [Hide] ormiston: 3:43pm Oct 24, 2008: thank you for this help! - my head is spinning. I have no room for a lengthy sentence - can it be made any neater than this ? (!) "statistically significant difference at the 95% confidence level from the +/- standard deviation" [Hide] John Peterson: 4:03pm Oct 24, 2008: I'd just say "the difference is statistically significant at the 95% confidence level". In my view, you don't need to mention the standard deviation - it's implied by 95% being equal to an area bounded by +/- 1 sd of a standardised normal distribution. [Hide] Andy THEODOROU: 8:54pm Oct 24, 2008: Hello John - should that read +/-1.96... ? [Hide] |