Is there a way to estimate the upper limit and lower limit of time for doing a work? Suppose we are learning a page of facts and want to estimate the upper and lower limit of time taken to do so. If we start estimating the time we will find that the pages are learned in some variable periods of time: 17 min, 16:45 min ...so on (during the experiment different sets of facts are learned by the same person and it is assumed that no major distraction happens - like phone call or any person intruding and no other work is done in the process or the process is abruptly stopped). Each page contains approximately 112 words. How can the upper limit and lower limit of time required to do the work be calculate?