The question is incomplete, the complete question is;
Anna is conducting an experiment to determine how weather affects cell phone reception. She is trying to decide the best way to conduct her experiment in order to collect meaningful data. Which of the following experiments would help Anna collect the best data? A. Test different cell phones in different locations on days with clear weather. B. Test different cell phones in different locations on days with rainy weather. C. Test a cell phone's reception in one location with clear weather and in another location with rainy weather. D. Test a cell phone's reception in the exact same location under various atmospheric conditions.
Answer:
D. Test a cell phone's reception in the exact same location under various atmospheric conditions.
Step-by-step explanation:
In this experiment that Anna intends to carry out, the independent variable is the atmospheric condition. The dependent variable must be the cell phone reception, it is expected to change with atmospheric conditions.
In order to obtain valid results, other factors such as such as type of cellphone and location (control variables) must be held constant so as to collect the best data.