Spencer sampled 50 students of a private school who were questioned about their scores in Mathematics. Spencer wants to test the hypothesis that the private school students score better than the general public which has an average of 62 marks with a population standard deviation of 7 marks. Z= If the sample mean is 65 marks, what is the z-score? Answers are rounded to the hundredths place. a.) -3.84
b.) 1.56
c.) 3.03
d.) -2.56