The PREeMPt study (Keen et al. 2018) aimed to investigate whether or not is was feasible to conduct a randomised controlled trial of pretransplant exercise (prehabilitation) in patients with multiple myeloma awaiting autologous haematopoietic stem cell transplantation. One of the feasibility outcomes was the recruitment rate defined as the number of participants recruited per month.

The PreEMPt consented and recruited 23 participants in 13 months of recruitment at a single centre, a recruitment rate of 1.8 participants per month.

The approximate standard error of the monthly recruitment rate is:

A. 0.37 B. 0.28 C. 1.50 D. 1.81 E. 2.05