Aresearcher has a hypothesis there is a relationship between cancer and stress. he sets out to measure how stressed patients were before they got cancer. he creates a questionnaire asking things like, "did you like your job? ", "did you have a happy home life? ", etc. during the study the researcher noticed that those with higher stress levels before cancer did not get as much asleep as those with lower levels. this leads him to begin measuring how much sleep each person used to get on the average night. he concludes that people with stress did not get much sleep, indicating a relationship between cancer and sleep levels. based on this information, is this study valid? based on this information, is this study valid? a) no, because the researcher did not measure what he claimed to measure (the relationship between cancer and stress levels) b) yes, because the researcher changed his focus based on valid responses from participants c) yes, because the researcher did have a result in the end that showed there was some relationship between two variables. d) no, because a relationship between variables can only be determined by an experiment