Cartman is offended by the numbers when he confuses the student's publically posted height differentials for a penis size chart. He takes it upon himself to "correctly" measure all the boys' penises and the results land him in anger management. While the anger management group rages out of control, a lone scientist tries to save the day with his discovery that there is a direct correlation between anger and penis size.
To correct this, he measures all of the class boy's penis sizes in the Boys bathroom. After finishing reckoning Butter's penis size, he then tries to leave the bathroom to post the results on the school bulletin board, but eventually becomes stopped by Kenny, Kyle and Stan who claim he needs to get his penis measured with a witness. Cartman tries to escape this by claiming his penis size is 13.7 inches long, Kyle denies this and Cartman gets angry.
Following, Clyde Donovan and Craig Tucker show the results by covering the height differentials, with a post called "Actual Boy's Penis Sizes." Cartman becomes outraged after the list shows his penis to be 1.2 inches. After exposing his true penis length to be 1.4 inches, Cartman gets called to see Principal Victoria. She becomes angry at Cartman for measuring the boys penises in the bathroom, and questions his motivation to all this. He asks her why she posted their penis sizes on the bulletin board, but later Cartman finds out his misunderstanding over what was posted. Principal Victoria tells Cartman that the original post were height differentials, which displayed how big the students have gotten since their last physical and that Cartman grew 1.2 inches.
Cartman is sent to see a therapist with his mother following the incident. The therapist wanted to test Cartman's anger issues by insulting Cartman by calling him fat. Cartman ignores the therapist and decides to be on his phone where he is actually texting the therapist's wife about her husband cheating on her for a 14-year old girl. After finishing insulting Cartman, the therapist gets a call from wife where is she upset and kills herself with a gun. Cartman then replies he is big boned, not fat.
Meanwhile, the school held a Parent Teacher Association meeting to alert parents that all of the fourth-grade boys had their penises measured in the boys' bathroom. Randy questions the Principal how the penises were measured. Randy then volunteered to teach the fourth-grade class how to properly measure one's penis.
Following the scene, Cartman attends an anger management seminar with his therapist and other people who also threw a tantrum that caused them to be forced to attend the seminar. Apparently, they're all bothered with the size of their penises being small in size that according to the chart they were in the below average (Red) zone.
In South Park Elementary, Randy teaches the boys how to measure their penis with some confusing calculus equation formula. However, the students found this lesson to be very complicated and did not understand what Randy was teaching them. However, Randy claims he has a penis of 6.3 inches and smiles.