ArrayCollection/Min Max Problem

I have an array collection and I am trying to find the Min/Max of the values in groups. For Example my array collection has 100 values. I want to find the Min Value/Max Value between 1 to 26, 2 to 27, 3 to 28 , etc.... I tried to create 2 for loops in each other but for some reason during debugging/tracing it outputs wrong numbers, but if i do breakpoint then step in. I get the correct values. So the question is is there a better way than what i am doing. I am just trying to create a Stochastic formula.