Hi Greg… In the dedicated data Session 4 , there is a question (recorded lecture timer 15:07 minutes) , which shows a frequency distribution of the height of 80 students and asks us to find the least possible range , the intervals of importance are 140-144 and 160-164 , so the least possible range as specified by you should be maximizing the least value and minimizing the max value , which in this case would be 160-144 = 16 , but since its an interval and the intervals have a corresponding frequency, don´t you think that there would be a frequency or a corresponding student (in this case) of both the minimum and maximum value of the intervals,. For e.g. the interval 140-144 has the frequency of 6 , so ideally there should be at least 1 student with a height of 140 centimeters. Similarly for the interval of 160-164 , the frequency given is 4 , so ideally there should be at least 1 student with height of 164 centimeters and that would change our answer to 164-140 = 24 , as if we take the highest value of lowest interval 140-144 i.e. 144 in this case, then it means that we are sure that no student belongs to the height group of 140 cm.