Step 1 :Given distances are \(7.18, 24, 3, 18\).
Step 2 :Calculate the mean (average) of the distances. The mean is \(13.045\).
Step 3 :Subtract the mean from each distance and square the result. The squared differences are \(34.398225000000004, 120.01202500000001, 100.902025, 24.552025\).
Step 4 :Find the mean of these squared differences. The mean of the squared differences is \(69.966075\).
Step 5 :Take the square root of the mean of the squared differences to find the standard deviation. The standard deviation is \(8.36\).
Step 6 :The standard deviation of the sample of distances is \(\boxed{8.36}\) miles.