Suppose that the class average for PSYC292 at the end of the course was 58% with a standard deviation of 19%. The instructor decides to rescale the scores to have a new mean of 72%.
a. If the instructor wants 10% of the class to earn a grade of 88% or greater, what should they set the standard deviation to?
b. If the original grade was 75%, what will the rescaled grade be? If the rescaled grade is 75%, what was the original grade? Round your answers to the nearest whole percentage. Note: If you were unable to compute a standard deviation in part (a), use a SD of 10 for the rescaled scores.