#### Answer

Period and frequency are reciprocals, so the true period will be larger than the one predicted by assuming the spring has no mass.

#### Work Step by Step

The relation between frequency, spring constant, and mass is given by equation 11-6b, $f = \frac{1}{2 \pi}\sqrt{\frac{k}{m}}$.
Because real springs have mass, the effective mass that is oscillating is greater than the mass in the equation. The true frequency will be smaller than the one predicted by assuming the spring has no mass.
Period and frequency are reciprocals, so the true period will be larger than the one predicted by assuming the spring has no mass.