In a trauma hospital, it was found that contractions of 300 grafts are normally distributed with a mean of 68 mm and a standard deviation of 3 mm. At 6 months:

a- How many grafts have shrinkage greater than 72 mm? b- How many less than or equal to 62 mm? c- How many between 65 and 71 mm?

Consider the following aspects when submitting your test: Present your answers with the aspects learned so far about probability and the normal distribution.