Specifications

balreal
16-18
1.0062e-01 6.8039e-05 1.0055e-05
which indicates that the last two states of sysb are weakly coupled tothe input
and output. You can then delete these states by
sysr = modred(sysb,[2 3],'del')
to obtain the following first-order approximation of the original system.
zpk(sysr)
Zero/pole/gain:
1.0001
--------
(s+4.97)
Compare the Bode responses of the original and reduced-order models.