Final answer:
Without the exact equation of the line of best fit, an exact number of predicted hot cocoa sales at 30°F cannot be given. However, one would typically use the equation from the line of best fit to predict sales relative to temperature.
Step-by-step explanation:
The student's question is about predicting the number of hot cocoas Salma would sell at the ice skating rink if the day's high temperature were 30°F, using a line of best fit from a plotted graph. To make predictions based on the line of best fit, one would generally use the equation of the line to find the y-value (the number of hot cocoas sold) corresponding to the x-value (the temperature, 30°F).
Unfortunately, since we do not have the exact equation of the line of best fit for Salma's sales data, we cannot provide an exact prediction for the number of hot cocoas sold at 30°F. To find the precise prediction from the line of best fit, we would need either the slope and y-intercept of the line or two points on the line to calculate these parameters.
Understanding how to determine if there is a relationship between two variables and whether it is due to coincidence or causation is fundamental in statistics and data analysis and is well demonstrated through exercises like plotting data and drawing lines of best fit.