N.C. Gen. Stat. § 8C-1, Rule 701: Opinion testimony by lay witness.

If the witness is not testifying as an expert, his testimony in the form of opinions or inferences is limited to those opinions or inferences which are (a) rationally based on the perception of the witness and (b) helpful to a clear understanding of his testimony or the determination of a fact in issue. (1983, c. 701, s. 1.)