Abstract
This paper aims to develop a practical method for making a wider range measurement of straightness, with good accuracy, possible, even thogh using a handy apparatus. An analysis based on the least square method is presented about the data coupling method employed, and basic matters concerning data treatments, error variances in measurement and the improvement of measuring accuracy are considered. A simple experimental apparatus aided by a personal computer is provided for actual measurements. Experiments bring about good results in the sense that the measuring operation based on the overlap coupling of data can be successfully made, and that measured values seem to have fairly good accuracy. Consequently, it is shown that the method employed has practical usefulness.
