Hypothesis testing

Jr. scientist A came up with a hypothesis and we decided to test it. He had discovered that the pump for his stomp rocket had a little nozzle that could be removed. He hypothesized that the nozzle, with its smaller opening, would result in less air being pushed out of the pump and thus the rocket would fly a shorter distance (personally I thought the smaller nozzle would result in greater pressure and thus a longer distance flight). We tested the hypothesis by setting up the stomp rocket and firing off rockets either with or without the nozzle in place. We marked each place the rocket landed - blue for with the nozzle and white for without. To my surprise, all three white lines (no nozzle) were farther than all three blue lines (with nozzle). This was a moderately well received introduction to rigorous hypothesis testing, but clearly a tad bit advanced for Jr. scientist A.