Final answer:
Zach can collect data points in Quadrant IV by measuring at night in southern hemisphere locations during their winter months (June, July, August).
Step-by-step explanation:
Zach can collect data points that would plot in Quadrant IV if he measures variables where his independent variable is positive and his dependent variable is negative. This corresponds to geographical locations in the world where it is nighttime when Zach is collecting the data, and the time of year should be when the nighttime temperatures there are typically above freezing, yet still cold enough that heat measurements (if he is measuring temperature) would be negative if measured in Celsius. A plausible scenario would be to collect data during the night in southern hemisphere locations during their winter months, which are June, July, and August.