Design: The teacher’s mark book which documented the forecasted grades for Physics in Cambridge AS and A-Level International Examinations from the year 2014 to 2018 was consulted and compared with the actual grades obtained by students over the same period.
Methodology: Two hundred and thirty-five (235) students’ results constitute the sampled population. Ahead of the time of final Cambridge International Examinations (CIE), some students who had withdrawn from the school system due to the fact that they are dead, terribly sick or gained admission into other higher institutions of learning and did not have their names on the CIE result broadsheets were disqualified from being part of the sampled population. This enabled the researchers to accurately compared the forecast grades of students who sat for CIE with the grades that they actually obtained. Shapiro-Wilk test of normality was carried out and the P-value was above 0.05 level of significance, as this shows that the data was parametric. SPSS version 23 was thereafter used to analyze the data and the hypothesis was tested using paired sample T- tests.
Results: There is no significant difference between Physics teacher’s forecast grades and the actual grades obtained by students in Cambridge Advanced AS and A-Level International Examinations for 5 years (2014 – 2018) as the teacher’s forecast grades for the last 7 examination series were accurate at P < 0> Conclusion: Findings from our study showed that there is no significant difference between Physics teacher’s forecast and the actual grades obtained by the students in the Cambridge Assessment International Education for October/November 2015, May/June 2016, October/November 2016, May/June 2017, October/November 2017, May/June 2018 as well as October/November 2018 examination series.