Study finds UV nail dryers used in gel manicures can damage DNA and cause mutations in human cells Researchers from the University of San Diego performed in vitro irradiation of cells derived from humans and mice to UV light from nail dryers, to evaluate DNA damage and mutations of cells. In the experiments, cells were irradiated one, two, or three times. In all the experiments, a single 20-minute irradiation resulted in 20-30% cell death, while three consecutive 20-minute exposures caused 65-70% cell death. Scientists say the results of their study, published in the scientific journal Nature, provide a comprehensive profile of the DNA damage and cell mutation that occurs after irradiation with nail polish dryers. They say further research in humans is needed before they can make definitive conclusions about cancer risks from exposure to UV nail polish dryers. a) Based on the title of the article, classify this study's hypothesis: a. Is the title a frequency, association, or causal claim? How do you know? b. What would be the null hypothesis for this study? c. What is a different alternative hypothesis that could be made for this study? b) Classify the study's variables: Variable name Is this an IV or a DV? (if it's a correlational study, put "a variable") Variable 1 Variable 2 Variable 3 Was this variable manipulated or measured? For IVs only: Was this manipulated as independent groups or within-groups? (if applicable) c) Is the article title an appropriate representation of the study design? Why or why not?