Word bank: Descriptive Bar graph Less Ordinal Ratio Interval Quantitative variable Central tendency Correlational study Variability Frequency polygon Variance Experiment Sample Greater Mode Nominal Mean Standard deviation Inferential Population Variable Median Histogram Researchers are examining the impact of rewarding children for coloring on the number of minutes they spend coloring. They put some children in a group that receives an award and others in a group that does not. This is an example of a(n)