Yeah, 95% confidence ratio (or approximately two standard deviations) is pretty standard with regards to statistical tests.
You gotta draw the line somewhere. At high-school statistics level, its basically universally drawn at the 95% confidence level. If you wanna draw new lines elsewhere, you gotta make new rules yourself and recalculate all the rules of thumb.
You gotta draw the line somewhere. At high-school statistics level, its basically universally drawn at the 95% confidence level. If you wanna draw new lines elsewhere, you gotta make new rules yourself and recalculate all the rules of thumb.