Answer: D) Qualitative data is not collected by instruments, it is just observations
Quantitative data deals with numeric values, which is collected by instruments usually. For example, if you're weighing various rocks, then each numeric weight value is part of the quantitative data set. The color of each rock would be qualitative data as you simply look at the rocks and record the color. It will depend on what question you're trying to answer as to whether quantitative data or qualitative data is more useful. Sometimes you may need both types.