1. The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. According to the Standard Deviation Rule, in a semester, almost all (99.7%) of the students spen on textbooks: between 215 and 255 dollars. between 195 and 275 dollars. between 175 and 295 dollars. less than 215 dollars or more than 255 dollars. above 235 dollars