In a simple random sample of 250 industrial workers with cancer, researchers found that 102 had worked at jobs classified as “high exposure” with respect to suspected cancer-causing agents. Of the remainder, 84 had worked at “moderate exposure” jobs, and 64 had experienced no known exposure because of their jobs. In an independent simple random sample of 250 industrial workers from the same area who had no history of cancer, 31 worked in “high exposure” jobs, 60 worked in

“moderate exposure” jobs, and 159 worked in jobs involving no known exposure to suspected cancercausing agents. Does it appear from these data that persons working in jobs that expose them to suspected cancer-causing agents have an increased risk of contracting cancer? Let a ¼ .05.