From birth to death, every man is under the control of the three biorhythm curves that initiate from inner body. body. Those are called 'Physical rhythm, emotion I rhythm and intellectual rhythm'. These biorhythms have influence each other in human behaviour like physical endurance, creativity, record of examination. The result of investigation indicates that the students' records in low level period are lower than those of in high. Therefore, it is verified statistically whether the biorhythm has effects on human ability in scholarly record or not. And also, this research calculates the average nixed-biorhythm which is representable for a group by using mode mixed-biorhythm.