The angiogram is a standard to detect stroke in patients. this test ha diagnostic test used in clinical medicine for the patient, and s some risks that are hoped to be the angiogram. one such method utilizes that several noninvasive techniques have been develope as efectve a erbral blood flow (cbf) in the brain, since stroke measurement of ral bloo patients tend to have lower levels of cbf than normal. among health people, cbf is normally distributed with mean 75 and standard deviation 17. patients are classified as being at risk for stroke if their cbf is below 40. what proportion of normal patients will be mistakenly classified as being at risk for stroke?