I would like to compare two experiments in term of their difficulties. I do not like to repeat the words in my sentences. For the comparison, I would like to use _much_more_ to show significant difficulty. I learned that much and more used for uncountable things, for example, sugar.
Here is my sentence:
The second experiments add extra computation which results in much more difficulties in comparison with the one of the first one.
Does use _much_more_ is acceptable in English sentences?
Much more is okay, but using it with much more difficulties is not. (Even much more difficulty is a bit odd.)
There are many word choices here, all depending on your intent. I will try to provide a few examples.
The second experiment involved extra computation, resulting in a much more difficult process than the first.
The second group of experiments requires additional computations; in comparison with the first group of experiments, these computations are much more difficult.
The experiments in the second group, because of extra computations, are much more difficult.
The second experiment added a complicated computation that presented a much greater degree of difficulty.
Note: You can add extra cheese to pizza, and you can add extra data to a mobile phone plan, but I believe that to add extra computation[s] in this context sounds a bit redundant. (I would say there are extra computations, there are added computations, or I will add another computation.) However, that may just be my personal style.
I didn't understand what you meant by with one of the first one as it related to the overall sentence, so I didn't try to interpret it.
The second experiment exhibits greater complexity in both design and execution than the first experiment.
That said the question becomes one of the type of experiment being considered. Is it a random controlled trial (RCT, e.g., test vs control groups based on some assumptions of random sampling) where hypotheses are formulated, data is collected and tests are performed or is it more in the nature of an exploratory, qualitative thought experiment or, perhaps, an anthropological or ethnographic study? Describing what is meant by the word computation would resolve this.
The point is that in the former case of an RCT it would be possible to statistically evaluate or quantify the increased degree of complexity using readily available metrics (e.g., AIC, BIC). The latter type of experiment does not readily lend itself to such an 'objective' evaluation and quantification.
