Question

You are developing a procedure for determining traces of copper in biological materials using wet digestion followed by measurement by atomic absorption spectrophotometry. In order to test the validity of the method, you obtain an NIST orchard leaves standard reference material and analyze the this material. Five replicas are sampled and analyzed, and the mean of the results is found to be 10.8 ppm with a standard deviation of LaTeX: \pm

±

0.7 ppm. The listed value is 11.7 ppm.

Does your method give a statistically correct value at the 95% confidence level?

Answer 1

So see final value come 11.67 ppm

To Construct 95% interval We require x tts x = mcom 210.8 sa sla deviation = 0.7 one sample size. to tscore To find t score of Freedom 2) - 0.95)/2 = 0.25 alpha level From t table a get =tscore 22.776 . 10.8+2.776 *0.7 = 11.67 1) sample size -1 = 5-12 4 Degree

so my method is not giving value in 95% confidence interval.