Defendant’s first assignment of error is based on his Exception No. 2. By this assignment defendant contends that the court erred in allowing the assistant district attorney to repeatedly ask Robert Carmichael leading questions, particularly with reference tó the time he left home on the morning of the murder.
Robert Carmichael testified on cross-examination that he awoke at approximately 7:00 a.m. and arrived at defendant’s at approximately 7:15 a.m.; that he based that on the fact that his brothers left about five minutes earlier than he every day; that he did not have a watch; and that he “really didn’t know” what time he left. He was then asked by the assistant district attorney on redirect examination:
“Q.. All right, did you in fact then base your time estimate .to start with—
“Mr. Cherry: Object to leading, your Honor.
“Q. Is that the only basis on which you estimate that you left your house about seven fifteen?
“Q. Could it have been seven-thirty that you left your house?
“Mr. Cherry: Objection. Move to strike.
“Court: Overruled. Defendant’s Exception No. 2.”
Only three questions were asked. The trial court sustained the objection to one of these. No objection wás made to the second, so only the third question forms the basis for this, assignment. •:
' The record discloses that-the witness was not sure of the1 time he left.the house, and the assistant district attorney was *444simply trying to clarify this. Defendant himself testified that he got up about 7:30 a.m. and that a Carmichael boy came by while he was dressing. In view of this testimony by defendant, we do not see how he could have been prejudiced by Robert Carmichael’s answer that he could have left his home at 7:30 a.m. rather than 7:15 a.m.
Furthermore, this Court has wisely and almost invariably held that the presiding judge has wide discretion in permitting or restricting leading questions. When the testimony so elicited is competent and there is no abuse of discretion, defendant’s exception thereto will not be sustained. 2 Wharton’s Criminal Evidence § 412 (13th ed. 1972) ; State v. Greene, 285 N.C. 482, 206 S.E. 2d 229 (1974) ; State v. Bass, 280 N.C. 435, 186 S.E. 2d 384 (1972) ; State v. Clanton, 278 N.C. 502, 180 S.E. 2d 5 (1971) ; State v. Painter, 265 N.C. 277, 144 S.E. 2d 6 (1965) ; State v. Pearson, 258 N.C. 188, 128 S.E. 2d 251 (1962). We hold that, in allowing the single leading question here presented, the trial court did not abuse its discretion.
 During the course of the trial defendant offered as a witness Mr. Charles Whitman, a Special Agent with the North Carolina State Bureau of Investigation. His testimony was taken out of the' presence of the jury. Mr. Whitman testified that he is a polygraph examiner with the State Bureau of Investigation and recited in detail his qualifications for such position. He further testified that he saw defendant on 2 April 1974 in Morgan-ton, North Carolina* and at the request of Captain Studer of the Fayetteville Police Department administered a polygraph examination to defendant. He testified regarding the procedures he followed and the results of the examination. The trial court ruled this testimony inadmissible.
Defendant’s counsel in his brief states: “It is readily conceded that the present rule in North Carolina and the majority of jurisdictions is that the results of a polygraph examination may not be used in Court to show either innocence or guilt. ...” Defendant, however, contends that in this case a proper foundation was laid for the admission of this testimony in that defendant voluntarily submitted to the polygraph test, the test was administered by a competent qualified examiner, and the results of the test would have been beneficial to defendant’s case, and that the exclusion of this evidence was therefore prejudicial error.
*445In State v. Foye, 254 N.C. 704, 120 S.E. 2d 169 (1961), we held such evidence inadmissible. Chief Justice Winborne there reviewed the authorities from other jurisdictions stating various reasons why results of such tests were not admissible and then concluded:
“ . . . [W]e are of opinion that the foregoing enumerated difficulties alone [lack of general scientific recognition, tendency to distract the jury, inability to cross-examine machine, no corresponding necessity for submission to tests by the prosecution] in conjunction with the lie detector use presents obstacles to its acceptability as an instrument of evidence in the trial of criminal cases, notwithstanding its recognized utility in the field of discovery and investigation, for uncovering clues and obtaining confessions. This conclusion is in line with the weight of authority repudiating the lie detector as an instrument of evidence in the trial of criminal cases.”
Defendant urges us to reconsider our decision in Foye in light of technological and judicial advances since Foye was decided in 1961. The weight of authority still supports that decision. See Annot., 23 A.L.R. 2d 1306 (Later Case Service 1970 and Later Case Service 1975) ; 29 Am. Jur. 2d, Evidence § 831 (1967). We see no compelling reason to change our ruling and we adhere to our decision in Foye for the reasons stated therein.
The jury, after having deliberated for some time, returned into court and asked the trial judge to again explain the difference between first degree and second degree murder. The trial judge did so, and defendant’s counsel concedes that the trial judge’s initial and supplemental charges with reference to the various elements of first and second degree murder were correct.
 After the supplemental charge, the jury again returned and asked the trial judge for a “couple” of definitions:
“One is what is the meaning of cool blood or cold blood, and the other one you have already stated two or three times, but we need it one more time, I guess, and that is the time limit in premeditated and deliberate deliberation, whatever it may be.”
The trial judge then repeated that portion of his charge which correctly defined premeditation and deliberation.
*446The foreman of the jury then asked for a definition of cool ■blood. The court gave an acceptable definition of cool blood, to which defendant did not object. The foreman then said:
“Sir, could I ask one more question?
“Court: All right.
“Foreman : Would this be what in my time and in my years past we have heard as a cold blooded killing, is that what it would mean, about the same thing?
“Exception Dependant’s Exception No. 17.
“Court: Yes, sir.
“Foreman: Thank you, sir.”
Defendant assigns this answer as error. While we do not approve this answer, and the trial judge would have been well advised to have reminded the jury that he had explained the meaning of cool blood, and to have referred to and if necessary repeated that explanation, we do not believe this answer is so prejudicial as to require a new trial. The charge of the court must be construed contextually and segregated portions will not be held prejudicial error when the charge as a whole is free from objection. State v. Bailey, 280 N.C. 264, 185 S.E. 2d 683 (1972) ; State v. Alexander, 279 N.C. 527, 184 S.E. 2d 274 (1971) ; State v. McWilliams, 277 N.C. 680, 178 S.E. 2d 476 (1971) ; State v. Gatling, 275 N.C. 625, 170 S.E. 2d 593 (1969). See 3 Strong, N. C. Index 2d, Criminal Law § 168 (1967).
“ . . . Premeditation means ‘thought beforehand’ for some length of time, however short. [Citation omitted.] This Court said in State v. Benson, 183 N.C. 795, 111 S.E. 869: ‘Deliberation means ... an intention to kill, executed by the defendant in a cool state of blood, in furtherance of a fixed design ... or to accomplish some unlawful purpose, and not under the influence of a violent passion, suddenly aroused by some lawful or just cause or legal provocation.’ [Citations omitted.] No fixed amount of time is required for the mental processes of premeditation and deliberation constituting an element of the offense of murder in the first degree, it being sufficient if these mental processes *447occur prior to, and not simultaneously with, the killing. [Citations omitted.]”
The instructions given by the trial judge to the jury on the question of premeditation and deliberation on at least three occasions were in substantial accord with these well settled principles of law. State v. Britt, 285 N.C. 256, 204 S.E. 2d 817 (1974); State v. Sanders, supra. The answer of the trial judge to the question of the foreman of the jury that “cold blooded” means about the same thing as killing in cool blood is manifestly not repugnant to the prior instructions. Hence, we are not presented with a situation where the judge gave conflicting instructions on a material point. Compare State v. Starnes, 220 N.C. 384, 17 S.E. 2d 346 (1941) ; State v. Bush, 184 N.C. 778, 114 S.E. 831 (1922).
To warrant a new trial it should be made to appear that the ruling complained of was material and prejudicial to defendant’s rights and that a different result would have likely ensued. State v. Sanders, supra; State v. Paige, 272 N.C. 417, 158 S.E. 2d 522 (1968) ; State v. Woolard, 260 N.C. 133, 132 S.E. 2d 364 (1963) ; State v. Beal, 199 N.C. 278, 154 S.E. 604 (1930). In view of the viciousness of the assault, which resulted in the death of the child in this case, we do not think that the trial court’s answer to the question posed by the foreman affected the result. This assignment is overruled.
 In State v. Waddell, 282 N.C. 431, 194 S.E. 2d 19 (1973), we held that due to the decision of the Supreme Court of the United States in Furman v. Georgia, 408 U.S. 238, 33 L.Ed. 2d 346, 92 S.Ct. 2726 (1972), the “ . . . mandatory death penalty for ... murder in the first degree . . . may not be constitutionally applied to any offense committed prior to the date of this decision but shall be applied to any such offense committed after such date.” Waddell was decided 18 January 1973. The murder in the present case was committed on 22 February 1972. Hence, on the jury’s verdict of guilty of murder in the first degree, the trial court correctly imposed judgment that defendant be imprisoned for the term of his natural life.
There were many discrepancies and contradictions in the testimony. For example, Robert Carmichael, principal witness for the State, at one time said that defendant did not kill Vanessa Dale Lewis, and that Lee Junior Brunson did. Lee Junior Brunson at one time told the officers that it was his brother *448Leon rather than James who came to the house with blood on his clothes. Such discrepancies and contradictions go to the credibility of the witness and not necessarily to the competency of the testimony. We are mindful of the fact that the jury observed the witnesses as they gave their testimony and that the probative value of their testimony was solely for determination by the jury. Such discrepancies and contradictions in the State’s evidence are matters for the jury and not the court. Sneed v. Lions Club, 273 N.C. 98, 159 S.E. 2d 770 (1968) ; State v. Burell, 252 N.C. 115, 113 S.E. 2d 16 (1960) ; State v. Bryant, 250 N.C. 113, 108 S.E. 2d 128 (1959) ; State v. Humphrey, 236 N.C. 608, 73 S.E. 2d 479 (1952). The jury has resolved any doubts against defendant.
After a full and careful review, we conclude that defendant has had a trial free from error, and that the judgment imposed should be affirmed. In the record we find no error.