Dogs were trained with urine samples from bladder cancer patients and people from a control group who did not have bladder cancer. Results are in the table below. Using a 0.01 significance level, test the claim that the source of the 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 diagnosis?
Sample with cancer Sample w/o cancer
Dog identified subjects as cancerous 22 32
Dog did not identify subject as cancerous 32 282
The solution tests for independence of variables using chi square test.