Compare the two groups of data. which statement is true? a) on average test scores for mr. scarlet's class and mrs. plum's class are equal b) on average test scores for mrs. plum's class are 4 points higher than mr. scarlet's class c) on average test scores for mrs. plum's class are 6 points higher than mr. scarlet's class d) on average test scores for mrs. plum's class are 14 points higher than mr. scarlet's class