Answer
False
Work Step by Step
The boundary for $6$, $5.9-6.1$ inches, is not correct as it does not include 5.5, 5.6, 5.7, 5.8, 6.2, 6.3,6.4. Each of these values, when rounded off, give 6 and they should therefore be part of the boundary.
The boundary of a number is defined as a class in which a data value would be placed before the data value was rounded. Therefore, for $6$ inches, the boundary would instead be $5.5-6.5$ inches.