1. The problem asks: Based on the research goal, what is the explanatory variable when determining if the speed of the ball hit predicts the distance it travels? 2. In regression and correlation analysis, the explanatory variable (independent variable) is the one used to predict or explain changes in another variable (dependent variable). 3. Here, the researcher wants to see if speed can predict distance. Therefore, speed is the explanatory variable, and distance is the response variable. 4. So, the explanatory variable is **Speed**. Final answer: Speed