An atomic absorption method for the determination of the amount of iron present in used jet engine oil was found from pooling 30 triplicate analyses to have a standard deviation s=3.7gFe/mL. How many replicate measurements are needed to decrease the 95 and 99% confidence limits to 2.1gFe/mL ? Remember that you always need to round your final answer up to a whole number of replicates. For the 95% confidence limit, N For the 99% confidence limit, N