The mean length of a set ribbons is 30 inches. the standard deviation is 11 inches. describe the data that is within on standard deviation of the mean?

It would fall under a normal data curve. However, because the standard deviation is so large, we would feel less confident after 2 standard deviations than normally. So we'll share some probability given just the first two standard deviations. 

19 to 41 inches - 68.37% likely to fall within this range. 
8 to 52 inches - 95.45% likely to fall within this range.