Final answer:
The behavior falling within 2 standard deviations of the mean in a normal distribution is typically described as usual or typical, as it encompasses about 95 percent of the data according to the Empirical Rule.
Step-by-step explanation:
The term that best describes behavior that falls within 2 standard deviations (SD) of the mean in a normal distribution is typical or usual because according to the Empirical Rule, approximately 95 percent of the data in a normal distribution lies within two standard deviations of the mean. This is under the assumption that the distribution is bell-shaped and symmetric. For example, if the mean (μ) of a data set is 50 and the standard deviation (σ) is 6, about 95 percent of the x values would be expected to lie between 38 (50 - 12) and 62 (50 + 12), where 12 is calculated as 2 times the standard deviation (2σ).