A researcher in Palestine wanted to test if a new cancer treatment would be successful in treating lung cancer. Using Palestinian patient records, she randomly selected 20 patients from every stage of lung cancer (stage 1 cancer, stage 2 cancer and stage 3 cancer) to participate in the study. She randomly assigned half of them to receive the new treatment and the other half to receive the old traditional chemotherapy treatment. After a few weeks, she tested their progress by measuring the size of their tumor (in centimeters). Use this information for all the parts. Part 2: When the researcher randomly selected 20 patients from each stage of lung cancer, what type of sampling method did she use