Hello!
![\boxed{ \bf 4.}](https://img.qammunity.org/2019/formulas/mathematics/high-school/lrecxka6mth4ft0il8wl3pjhohxsvd08ov.png)
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![\bf Explanation:](https://img.qammunity.org/2019/formulas/english/college/g7c4xzhgpeztkj494jwa0stkw5622ifdn5.png)
An outlier is a value that lies outside or is different from most of the values in a data set. In this set, 47, 48, 49, 53, and 54 are quite close to each other. The difference between 54 and 47 is 7. The difference between 4 and these numbers is quite big, which is what makes it the outlier of the data set.