(Assuming the the magnitude of the experiment 1 results aren't erroneous (despite statically significant different to the other 3 counts of experiment 1 results when a t.test is applied; ρ = 0.0431)), The issues with these results is there's no clear increase in CPM when glucose is added in experiment 2. I would assume the error occurred in adding the glucose in experiment 2. I would suggest the error occurred was that instead of adding 0.25ml, the experimenter read the instructions as 0.25ul, or had miscalibrated their pipette, resulting in the glucose added being a factor of 10x or 100x smaller than the glucose that should have been added, leading to no effective change in CPM.