Defendant assigns as error the trial judge’s inquiry as to the numerical division of the jury, his reinstruction as to the elements of the offense, his response to a question that instructed the jury to lay down its own rules as to the weight to give unrebutted testimony of a witness, and the imposition of a sentence that was more than twice the presumptive sentence. We find no reversible error in any of the trial judge’s questions and instructions to the jury, but we remand for a new sentencing hearing because of error committed in the sentencing phase.
[1] Defendant urges that it is per se reversible error to inquire into a jury’s numerical division. Brasfield v. United States, 272 U.S. 448, 71 L. Ed. 345, 47 S.Ct. 135 (1926), prohibited inquiries into the jury’s numerical division in federal criminal cases, but this prohibition is based on the Supreme Court’s supervisory power over lower federal courts, is not constitutionally based, and is a rule of procedure for federal courts that is not binding on state courts. Ellis v. Reed, 596 F. 2d 1195 (4th Cir.), cert. denied, 444 U.S. 973, 62 L.Ed. 2d 388, 100 S.Ct. 468 (1979). The context of inquiry as to the jury’s numerical split may show that the inquiry is coercive, but we hold that such an inquiry is not inherently coercive or violative of the North Carolina Constitution’s Article I, § 24 guarantee of the right to a trial by jury. In the absence of a federal or state constitutional basis requiring the adoption of a per se rule, we will look to the “totality of the circumstances” in evaluating a trial judge’s inquiry as to a jury’s numerical split. An inquiry is often useful in timing recesses, in determining whether there has been any progress toward verdict, and in deciding whether to declare a mistrial because of a deadlocked jury. We must examine the trial judge’s inquiry in context of the totality of the circumstances to determine whether the trial judge’s inquiry was coercive or whether the jury’s decision was in any way affected by the inquiry. See State v. Williams, 303 N.C. 142, 277 S.E. 2d 434 (1981); State v. Barnes, 26 N.C. App. 37, 214 S.E. 2d *503806 (1975). In this case, the trial judge made his inquiry as to the numerical split at a natural break in the jury’s deliberations, after a full morning’s deliberations, and clearly stated that he did “not want to know that so many jurors have voted in one fashion and so many in another.” From the totality of the circumstances, we find no coercion and no error in the trial judge’s inquiry.
[2] Using the same “totality of the circumstances” analysis, we now consider defendant’s second assignment of error concerning the trial judge’s reinstruction of the jury on the elements of the offense. There was nothing in the trial judge’s reinstruction as to the elements of the offense that could be considered prejudicial or coercive. The trial judge simply restated the elements of the offense and the application of the law to the facts. There was nothing in the reinstruction that implied any opinion on the part of the trial judge or would affect the jury’s ultimate decision. The fact that the jury came back to ask a question after the reinstruction was given and then deliberated further indicates that this jury was not coerced by the judge’s reinstruction.
[3] Defendant next assigns as error the trial judge’s instruction to the jury that it must govern itself in determining what weight to give to unrebutted testimony. There is no error in this instruction, which was given in response to a question, because the jury is allowed, in weighing credibility of evidence, to consider the fact that the evidence is uncontradicted or unrebutted. State v. Tilley, 292 N.C. 132, 143, 232 S.E. 2d 433, 441 (1977). In any event, because defendant did not make timely objection to this jury instruction, his objection is waived. N.C. R. App. P. 10(b).
[4] Defendant’s final assignment of error concerns the sentencing phase of his trial. Defendant received a thirty year sentence for armed robbery, a Class D felony, for which the presumptive sentence is ordinarily twelve years. G.S. 14-87(a) and G.S. 15A-1340.4(f)(2). However, the armed robbery statute requires a minimum sentence of fourteen years. G.S. 14-87(a). This court has held that, for armed robbery, fourteen years is both the minimum and the presumptive sentence. State v. Morris, 59 N.C. App. 157, 296 S.E. 2d 309 (1982); State v. Leeper, 59 N.C. App. 199, 296 S.E. 2d 7 (1982). Therefore, the fourteen year sentence may be increased by the process of weighing aggravating and mitigating factors, but a sentence of less than fourteen years may not be im*504posed for armed robbery. In this case, the trial judge imposed a sentence that was more than twice the presumptive sentence, relying on two aggravating factors and no mitigating factors. We hold that the trial judge improperly found one aggravating factor.
The trial judge found as an aggravating factor that the defendant used a deadly weapon at the time of the crime. See G.S. 15A-1340.4(a)(1)(i). Use of a deadly weapon is an element of the offense of armed robbery. The Fair Sentencing Act dictates that “evidence necessary to prove an element of the offense may not be used to prove any factor in aggravation.” G.S. 15A-1340.4(a)(1); State v. Setzer, 61 N.C. App. 500, 301 S.E. 2d 107 (1983).
[5] Defendant contends there was a second error in the sentencing phase of this trial: the trial judge’s failure to find as a mitigating factor that the defendant testified for the State in another felony prosecution. See G.S. 15A-1340.4(a)(2)(h). At the sentencing hearing, defendant told the trial judge that he had testified for the State in a case where an inmate had murdered a prison employee. There was no other evidence presented to support or rebut this claim by defendant. Our Supreme Court has recently said that “when evidence in support of a particular mitigating or aggravating factor is uncontradicted, substantial, and there is no reason to doubt its credibility, to permit the sentencing judge simply to ignore it would eviscerate the Fair Sentencing Act.” State v. Jones, 309 N.C. 214, 218-19, 306 S.E. 2d 451, 454 (1983). The Jones decision makes it clear that the burden of persuasion on mitigating factors rests on the defendant and that, to hold that the trial judge improperly failed to consider a mitigating factor, we must find that the credibility of the evidence is “manifest as a matter of law.” Id. Here, defendant’s unsubstantiated claim, though uncontradicted, is not substantial evidence and, absent corroborative evidence, does leave a basis to doubt its credibility. We hold that the record in this case does not present us with sufficient evidence to require the trial judge to find this mitigating factor.
We find no error in defendant’s trial, but because of error in finding one aggravating factor, we hold that defendant is entitled to a new sentencing hearing. State v. Ahearn, 307 N.C. 584, 300 S.E. 2d 689 (1983).
*505No error in defendant’s trial; remand for re-sentencing.
Judges Arnold and Wells concur.