What is the Level of Significance and how do I figure out what it is mathmatically?

Answer 1

the level is a chosen level to give your answer real validity or not. For most stats in medical research a 95% level is chosen. In other words there is only a five percent chance that the result is invalid. This is signified p < 0.05. If you have a result from a sample size of three: eg my 3 friends all eat chesseburgers therefore everybodsy eats cheezeburgers. Look up the tabel of significance values at it will tell you a sample size of three gives you a significance level of about p < .90 in other words you have only a ten percent chacne of being right and 90% chance of being wrong! If you have a sample of 1500 US people and you find that 70% of them eat cheesebrugers - because of your large sample size your result is likely to be valid at the 95% level of significance; ie at p < .05. so you can say with confidence that about 70% of all US people eat cheesburgers. Hope this helps.

Answer 2

It really depends on the spectre you are talking about...In terms of the whole Universe (for instance) or just your town (etc).