A complex organic compound contains a chemical which decays when the compound is removed from living tissue. If p is the proportion of the chemical present at the time of removal (t = 0), the proportion present at time t is pet where (>0) is known. To determine p a quantity of the compound is removed and independent, unbiased estimates are made of the proportions present at times = rr (r = 0, 1, 2, ..., N) in individual experiments each of which is of duration 7, the estimates having variances ke (i.e. proportional to the proportion present at the begin- ning of each experiment). Determine the best estimate of p and its variance when N is large. A second method of determination is suggested in which each experi- ment is twice as quick (i.e. 7 is reduced to r) but with each variance increased by 50%. Show that this second method is only better if.