In the Formula $$\bar { X } \pm z _ { a/2 } ( \sigma / \sqrt { n } )$$

True/False

In the formula $$\bar { X } \pm z _ { a/2 } ( \sigma / \sqrt { n } )$$ , the subscript $$\alpha / 2$$ refers to the area in the lower tail or upper tail of the sampling distribution of the sample mean.