Quantitative variable

Quantitative values are numbers that measure how much or how many, so you can add and average them. For example, height in centimeters, age in years, and number of siblings are all quantitative. You summarize this kind of data with measures like the mean $\bar{x}$ (x-bar) and standard deviation, and display it with dotplots or histograms. Averaging the values 4, 5, and 9 gives $(4 + 5 + 9) / 3 = 6$.