There is provided is a method and computer program product for selecting an appropriate golf ball for a subject by using a mobile computer device with a camera. The method includes: inputting information concerning hitting skill of the subject to the mobile computer device; performing a calibration of a distance and/or direction between two points in a screen of the mobile computer for shooting a moving image; shooting a moving image by the camera of the mobile computer device when the subject hits a golf ball by a golf club; determining a head speed of the golf club before an impact of the club and the ball from the shot moving image based on the calibration; computing a golf ball product having a suitable performance for the subject from the input information concerning hitting skill and the determined head speed, based on a database comprising data of information concerning hitting skills of players, data of head speeds before impact of club and ball, and data of performances of golf ball products which are correlated with each other; and displaying the computed recommended golf ball product on the mobile computer device.