2. What is a Grubbs test? How do you perform the calculations for a Grubbs test? 3. A reference material known to contain 1.00 % by weight of Iron is studied by four different analysts (1-4), each analyst performs 5 replicate measurements. The results are shown in the table below: Analyst 1 2 3 4 Replicate 1 1.03 0.98 1.16 0.98 Replicate 2 1.04 0.88 1.01 1.03 Replicate 3 1.03 1.09 Measurement 1 Se (g/g) 0.05 1.13 1.02 Replicate 4 1.07 1.06 2 0.07 1.04 0.99 Identify the errors in the analyst's measurements as random or systematic, and suggest an approach to correct the errors and provide a reliable result. Analyst 1: Analyst 2: Analyst 3: Analyst 4: 4. In order to investigate the reproducibility of a method for the determination of selenium in foods, five measurements were made on a single batch of brown rice. The results are listed below. 3 0.05 Replicates 1.07 0.94 1.26 1.03 4 0.05 5 0.06 Calculate the mean and the standard deviation for these values. Give an informed conclusion of the quality of the method.