The purpose of this study is to develope a web site of statistics closely related to real life in the information society and to analyze the achievement and the response of the students about WBI between the web based instructiongroup and the traditional instruction group after applied the developed web site. The conclusions drawn from the results of this study are as follows: First, as compared the web based instructionclass with the traditional instruction class there was a significant difference in the high class but not in the low class. And there was a higher level of the achievement in the web based instruction classes than the traditional classes. Therefore, it is certain that the achievement will not fall through the web based instruction is applied. Second, the results of the investigated response using the paper sheets in order to see the response of the students about the web based instruction is that there was a more effect related to the interest and understand of studying in the web based instruction than in the traditional instruction. As synthesizing these study results, there will be a positive effect on the mathematical achievement as well as the interest of students about mathematics if the web based instruction is properly used.