title: Value of whisker in boxplot for 99.7 coverage
body: <p>I am trying to identify outliers from a boxplot using MATLAB. The function has a default whisker value of 1.5 that provides +- 2.7*sigma or 99.3 coverage. 
  However, I want 99.7 or 3*sigma coverage. What could be the value of whisker in this case?
  I did not want to make a random guess, so need help from you guys.
  Thanks</p>