Rui is a teenage girl. One night Rui's father brings home a co-worker Mr. Igarashi. Rui is quite smitten with Mr. Igarashi and tells her father that she is interesting in learning about statistics so that she can be tutored by Mr. Igarashi. The day of her first lesson, instead of Mr. Igarashi it is another of her father's co-workers who shows up, Mamoru Yamamoto. Rui is crushed but plunges ahead, heart still set on hooking up with Mr. Igarashi. Part of the Edu-Manga line, this teaches about statistics. The second volume is about Factor Analysis, and the third is about Regression Analysis. These two volumes has the additional author INOUE Iroha.