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 Replicate 1 Replicate 2 Replicate 3 Replicate 4 Replicate5 1 1.03 1.04 1.03 1.07 1.07 2 0.98 0.88 1.09 1.06 0.94 3 1.16 1.01 1.13 1.04 1.26 0.98 1.03 1.02 0.99 1.03 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 reproduciblety 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. Measurement 1 2 3 4 5 Se (ug/g) 0.05 0.07 0.05 0.05 0.06 Calculate the mean and the standard deviation for these values. Give an informed conclusion of the quality of the method