Jananas said: For context this is the main task; Water is being transfered from its source (e.g a river) to a lab and all samples must be analysed during the travel to the lab, which is 1h. This is done 11 times during the trip, taking 4 determinations for each time. The concentration of aluminium is measured, and the goal is to keep it as close to the initial value as possible during the whole trip; View attachment 44458 Which checks out removing nr 1since its not statistically comparable with the rest. Will need to see what this means practically though... Click to expand... From task 2, you've concluded that the variability of the sample (1) is statistically different from other samples. Therefore, during the first 4 minutes, the sample will be unstable. If you were the researcher, you should wait longer than 4 minutes for the sample to stabilize before proceeding any further.