Answer Happy

A new flame atomic-absorption spectroscopic method of determining antimony in the atmosphere was compared with the recommended calorimetric method. For samples from an urban atmosphere the following results were obtained: Sample no. 1 2 3 4 5 6 Standard method Antimony found (mgm") 4.16 4.34 4.87 4.17 5.33 5.48 New method Antimony found (mg m) 4.38 4.15 4.76 4.42 4.80 4.74 (a) Compare the precision of the two methods and determine if the precisions of the two methods are significantly different or not, using a significand level of 0.05 (95 % confidence level). Assume that the data are normally distributed. Explain your results. (b) Determine if the means of the two methods differ significantly (95% confidence level). Assume that the data are normally distributed. Explain your results. Note: See appendix for tables and formulas you might need for your calculations