Can Dogs Detect Cancer? An experiment was conducted to test the ability of dogs to detect bladder cancer. Dogs were tested with urine samples from bladder cancer patients and people in a control group who did not have bladder cancer. Results are given in the table below (based on data from the New York Times). Using a 0.01 significance level, test the claim that the source of the sample (healthy or with bladder cancer) is independent of the dog’s selections. What do the results suggest about the ability of dogs to detect bladder cancer? If the dogs did significantly better than random guessing, did they do well enough to be used for accurate diagnoses?

Sample from Subject With Bladder Cancer Sample from Subject Without Bladder Cancer Dog Identified Subject as Cancerous 22 32 Dog Did Not Identify Subject as Cancerous 32 282