T Tests and P Value questions?

Question

We're doing a lab in Molecular Biology where we do a t-test comparing boys height vs boys arm span and girls height vs. girls arm span. The p value for BH vs. BAS is 0.9276 chich apparently means its not statistically significant. WHAT THE HECK DOES THAT MEAN????? Please put it in words according to a 9th grader please or put it words that anyone of any age could understand. Also it said the p value of GH vs. GAS(um...haha) was 0.0446 which apparently means the difference is statistically significant. WHAT DOES THAT MEAN?? I don't get p-values and what does it mean when its significant. PLEASE EXPLAIN IN WORDS THAT ANYONE OF ANY AGE COULD UNDERSTAND!!!!! thanks :]

Answer 1

The p-value = 0.9276 when you tested the difference between BH vs. BAS.  It means there is a 92.76% chance that BH is the same as BAS.  The p-value = 0.0446 means there is only a 4.46% chance that GH and GAS are the same.  

Answer 2

Ok so I will do my absolute best to put this in laymen's terms.  Basically there is a table of p values that exist and when two things are compared and found to have a p value that is less than 0.05, then it is statistically significant.  Statistically significant means that the two things are related to each other.  So for your two questions, a non-significant finding for the BH vs. BAS means that boy's height is not related to boy's arm span.  A significant finding for GH vs. GAS means that girl's height is related to their arm span.  I hope this cleared it up a bit.  If not, this is what my college-level textbook says on the matter.

"When we say that a difference is statistically significant at the 0.05 level, we mean that a difference that large would occur less than 5% of the time if the null hypothesis was true. "