In a standard normal distribution 95% of the data is within +/- standard deviations of the mean.
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Approximately 95% of a normal distributions falls within 2 standard deviations of the mean.

Your answer would be ahere is how: perimeter is how long all the sides are. in a rectangle, there are two sets of parallel sides. so, to find this, we would to the following.(15x2)+(4x2)30+838if you have questions ask! and mark me brainliest! i really wanna level up : 3