I have a good friend who has an experiment where he grows different kind of plants on various soils and measures the protein content and weight each week for 5 weeks. His goal is to determine which plant yields the best protein*weight results for each soil and on which week.
The data is fairly straightforward with columns: Soil, Plant, Time(Week), Weight, Protein/g
Initially this doesn't seem like a statistics related problem as I'd just group all data by soild and find the max value of Weight*Protein from the weeks for each plant. It should give me the best Plant-Time combination for each Soil.
The issue arises when my friend also mentioned that he has to do a One sample, two sample and paired t-test on the data without much context. He has no big knowledge in statistics so he couldn't provide me any more information.
One sample t-test should be executed against a specific mean value to determine whether or not the sample was taken from a population that has a similar mean.
Two sampled and paired t-test compares 2 sample sets and determines if they are from the same population or not. Paired also makes sure to make the comparison pair-wise instead of assuming the values are randomly chosen.
The protein and weight variables are not even normally distributed, therefore a t-test is a no-go in this case.
How can I even apply the t-test to this task so I can use it to find my answers?