I just need help with these questions :)

2. Raw scores on standardized tests are often transformed for easier comparison. A test of reading ability has a mean of 75 and a standard deviation of 10 when given to third-graders. Sixth- graders have a mean score of 82 and a standard deviation of 11 on the same test. (a) Eileen is a third-grade student who scores 78 on the test. Vicki is a sixth-grade student who scores 86. Calculate the z-score for each student. Who scored higher within his or her grade? Explain your reasoning. (b) Suppose that the distribution of scores in each grade is Normal. Determine the percentiles for Eileen and Vicki. Interpret these percentiles. (c) What percent of sixth-graders earn a score of at least 93 on the reading test