Solution– Let us assume that the nutritionist would like an intervalabout 10 grams wide; that is, the estimate should be withinabout 5 grams of the population mean in either direction. Inother words, a margin of error of 5 grams is desired. Let usalso assume that a confidence coefficient of 0.95 is decided onand that, from past experience, the nutritionist feels that thepopulation standard deviation is probably about 20 grams.The statistician now has the necessary information tocompute the sample size: z =1:96; = 20 and d = 5. Let usassume that the population of interest is large so that thestatistician may ignore the finite population correction.