What does the standard deviation tell you? I mean, I know that it shows the difference from the mean, but what does it tell you about two sets of numbers? For example, say two sets of numbers have the same mean, but one standard deviation is like 3.25 and the other one is 8.90. What does that symbolize?

Isuck at math ; ^; m a student solved this problem and said the answer is 3 feet. chase had a roll of ribbon that contained 7 7/8  feet of ribbon. he cut off one piece that was 3 5/8  feet long and another piece that was 1 1/4  feet from the roll. how much ribbon was left on the roll? is the student's answer reasonable? yes, the answer is reasonable. no, the answer is not reasonable. it should be about 2 feet. no, the answer is not reasonable. it should be about 13 feet. no, the answer is not reasonable. it should be about 4 feet.