Carotenoids are pigments responsible for much of the red we see in nature.They are also important antioxidants.Researchers hypothesized that carotenoids in birds may affect immune system function.To test this, 8 finches received supplemental carotenoids in their diet, while 6 other finches did not (no treatment).All 14 birds were then measured using an assay that measures immune system function, with higher values indicating better immune response.The data are given below.The data are not normally distributed and are not improved by transformation, so you want to conduct a Mann-Whitney U test on the data.

No treatment Carotenoid treatment 1.454 1.511 1.226 1.311 1.198 1.460 1.139 1.352 1.277 1.491 1.490 1.599 1.653 1.390