I think you're missing the rest of the question, but you can use the standard deviation and a normal curve to determine the likelihood that they'll fall into particular ranges. I've included some below for you.
61.4-67.6 - 68.37% likely to fall within this range.
58.3-70.7 - 95.45% likely to fall within this range.
55.2-73.8 - 99.73% likely to fall within this range.
