answer all questions with explanation

2. I want to know the average contamination level in a plot of ground. Just by looking at the area, I see that part has discolored soil and damaged plants. I'll put this area into one stratum and the rest of the area into another stratum. I collect n = 3 measurements in each stratum: Stratum One (appears contaminated): Area = 5 hectares, Measurements = 50 ppt, 100 ppt, 75 ppt. Stratum Two (appears uncontaminated): Area = 45 hectares, Measurements = 1 ppt, 3 ppt, 2 ppt. a) Find a 95 percent confidence interval for the true mean contamination level. b) Assuming that the cost of collecting data is the same everywhere, use the variances from the study to plan next year?s study, with a goal of getting an optimal allocation with a margin of error of 1 ppt