The sample median may or may not be an order statistic, since there is a single middle value only when the number of observations is odd. More precisely, if for some integer , then the sample median is formula_5 and so is an order statistic. On the other hand, when is even, and there are two middle values, formula_6 and formula_5, and the sample median is some function of the two (usually the average) and hence not an order statistic. Similar remarks apply to all sample quantiles.