A real spring is not massless, but the mass of your spring was not taken into account in experiment M19. How would the non-zero mass of your spring have affected your experimental values of the spring constant k and the oscillation period T?

k was not affected but the measured T were larger than the values predicted by the equation relating period, measured mass, and spring constant.

k was larger than expected but the measured T were not affected.

k was not affected but the measured T were smaller than the values predicted by the equation relating period, measured mass, and spring constant.

k was smaller than expected but the measured T were not affected.