The trial judge ordered that denial of an immediate appeal would affect a substantial right of plaintiffs. This was tantamount to a certification that there was no just reason for delay, and we conclude accordingly that the appeal has been effectively certified *75and is therefore properly before us. N.C. Gen. Stat. § 1A-1, R. Civ. P. 54(b) (1983).
Plaintiffs admitted during oral argument that the evidence present in the record before us does not present any genuine issue of material fact as to their allegations of corporate negligence by defendant Hospital. We agree. Nor is the question of the sufficiency of plaintiffs’ allegations of negligence on the part of Dr. Brantley, Rocky Mount OB-GYN Associates, P.A. or Dr. Henley before us on this appeal. Therefore the only question presented is whether the trial court erred in ruling that defendant was not liable on the theory of respondeat superior for the allegedly negligent acts of Doctors Brantley or Henley. For the reasons stated herein, we conclude that the order dismissing the action as to Nash General Hospital, Inc., should be affirmed.
Defendant Hospital’s liability, if any, depends upon whether either Dr. Brantley or Dr. Henley acted as its agent. Willoughby v. Wilkins, 65 N.C. App. 626, 310 S.E. 2d 90 (1983), disc. rev. denied, 310 N.C. 631, 315 S.E. 2d 697 (1984). Whether a principal-agent relationship exists is a question of fact for the jury when there is evidence tending to prove it; it is a question of law for the court if only one inference can be drawn from the facts. Partin v. Power & Light Co., 40 N.C. App. 630, 253 S.E. 2d 605, disc. rev. denied, 297 N.C. 611, 257 S.E. 2d 219 (1979). The key factor is whether or not the alleged principal has any power or control over the agent. Id.; Willoughby v. Wilkins, supra.
We conclude that no genuine issue of material fact exists as to whether or not Dr. Brantley was acting as an agent of defendant Hospital. As a matter of law, he was not. We rely on Smith v. Duke University, 219 N.C. 628, 14 S.E. 2d 643 (1941). There, as here, plaintiff was referred to the hospital by an outside agency and assigned to one of the private physicians practicing at the hospital, without any expression of preference by plaintiff. The Supreme Court held that the hospital assumed no liability for the independent professional activity of the attending physician, even though the physician (unlike Dr. Brantley) was on the payroll of the medical school associated with the hospital and maintained an office at the hospital. In Willoughby v. Wilkins, supra, and Rucker v. Hospital, 20 N.C. App. 650, 202 S.E. 2d 610, aff’d 285 N.C. 519, 206 S.E. 2d 196 (1974) we reached the opposite result. In *76each of those cases, however, the physician had signed a contract with the hospital agreeing inter alia not to maintain a private practice, to accept work as directed by the hospital and according to the policy of the hospital, and accepting salary and vacation from the hospital. Smith clearly is the controlling case here; once plaintiff was assigned to Dr. Brantley, according to a schedule worked out by the private physicians and not by defendant Hospital, she became his patient. Defendant Hospital did not bill plaintiff for Dr. Brantley’s services and did not supervise his activity. No liability can be imposed upon defendant Hospital based upon negligent treatment rendered by Dr. Brantley.
Therefore any liability of defendant Hospital may be predicated only on the acts of Dr. Henley. This presents an apparently novel question: whether residents assigned by a central medical school to outlying hospitals on a rotating basis are agents of the hospitals to which they are assigned.
It appears that Dr. Henley identified himself to plaintiff as a resident from UNC. He received his entire salary from UNC, and nothing from defendant Hospital. In providing individual patient care, Dr. Henley worked under the supervision of the attending physician in charge of the patient, in this case Dr. Brantley. There is nothing in the record to suggest that defendant Hospital’s personnel reviewed, supervised or controlled Dr. Henley’s activities, nor does it appear that defendant Hospital established any rules or regulations governing residents on rotation. Defendant Hospital apparently had no control over who would be assigned it by UNC or when. Applying the law set forth in Smith and Willoughby, supra, we conclude that defendant Hospital did not exercise that control over Dr. Henley necessary to impute to it liability for his acts. Waynick v. Reardon, 236 N.C. 116, 72 S.E. 2d 4 (1952), in which a resident was held to be the agent of the hospital, is clearly distinguishable. There the resident received a salary and accommodations from the hospital and was assigned certain duties by it; the resident performed the allegedly negligent surgery without the supervision of an attending physician.
Thus it appears that plaintiff has failed to establish that defendant Hospital has any liability on the theory of respondeat superior. Plaintiff attempts to save her case by reliance on her *77expert’s statement that other “hospital personnel,” in addition to Dr. Henley, were negligent. A careful review of the record does not reveal who these other personnel were or what they did or did not do that constituted negligence. Defendant Hospital did introduce affidavits from the attending nurses to the effect that they acted within the appropriate standards of care. It then became incumbent on plaintiff to come forward with some specific facts, as opposed to mere allegations, to establish defendant’s liability. Dickens v. Puryear, 302 N.C. 437, 276 S.E. 2d 325 (1981). The affidavit of plaintiff s expert, asserting that there was “inadequate and inappropriate immediate neonatal care of this infant by not only Dr. Henley but hospital personnel” and that the “failure of appropriate attention” was attributable “in part to the hospital,” contains only conclusory allegations, unsupported by any factual basis upon which the negligence of defendant Hospital or its personnel could be grounded, and is insufficient to defeat summary judgment. Nasco Equipment Co. v. Mason, 291 N.C. 145, 229 S.E. 2d 278 (1976).
We conclude that summary judgment was properly entered dismissing defendant Hospital from the case. The order appealed from is
Judges Arnold and Parker concur.