To predict when the surface of the moon will be fully visible, the student would have identified a maximum value on the graph. This is because the fully visible surface of the moon corresponds to the highest percentage of visibility, which is represented as the peak (maximum) of the regression curve.

Would you like a detailed explanation of how this choice relates to the graph's characteristics?

Here are some follow-up questions to explore this topic further:

1. What is the significance of the x-coordinate at the maximum value on this graph?
2. How does the regression function relate to the phases of the moon?
3. What other features of the graph can be analyzed to provide predictions (e.g., midline, minima)?
4. How can the midline of the graph be used to find average visibility over time?
5. How would the graph differ for other months or locations?

Tip: Always correlate the maximum and minimum values of periodic graphs with real-world phenomena when interpreting their meaning.