what's the cut off point

The following data represent the monthly phone use, in minutes, of a customer enrolled in a fraud prevention program for the past 20 months. The phone company decides to 395 498 562 0 use the upper fence as the cutoff point for the number of minutes at which the customer should be contacted. What is the cutoff point? 424 649 174 346 365 547 186 320 494 444 540 422 406 431 The culoit point is |minutes. ( Round to the nearest minute.)