Problem Explanation：
1. The principle of the wristband to measure the walking distance is to estimate the step length according to the height, gender and weight set by the owner, and then multiply the number of steps taken by the owner to get an estimated value.
2. Since the step length varies from person to person, people of the same height, gender and weight may also have different step lengths, so the final calculated value will have a large error.
3. There are many uncertain factors will follow each person's behavior will influence a lot, such as the size of arm waving the habit of walking activity and human activities such as the scene more (such as walking, driving, driving, taking a bath, etc), the arm movements more complex (such as keystrokes, move the mouse, lift pulling, etc).
4. With the above reasons, the final calculated distance of the band is also an estimated value, and the band cannot be used as a professional measuring tool to measure the distance.In the future, the software algorithm will be continuously optimized to calculate a more accurate data.