How to check the significant difference of pre- and post test result? [closed]

If I got a t -value=1.46988E-27, what does it signifies? How to find whether it is significant or not? And in what level it should be compared eg. 0.05 or 0.01 etc.

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 What do you mean by t-value? The p-value of the test, or the value of the t statistic? What do you mean by pre- and post- test significance (I am not aware of signficance before doing a test)? – gui11aume May 26 '12 at 15:40 -1, please provide more details. – mpiktas May 28 '12 at 17:31

closed as not a real question by whuber♦May 28 '12 at 18:52

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.

 It appears as though the $t$-statistic is $10^{-27}$, which would almost certainly indicate non-significance. – Macro May 26 '12 at 16:47 @macro Yes you interpreted what the OP said literally which would indicate a t of almost 0 which would be non-significant. But I assumed he meant the tail probability for the t statistic because he is looking at it as an indication of significance and numbers that small are in practice often seen as p-value but rarely as calculated values for the test statistic. – Michael Chernick May 26 '12 at 17:02