The midterm exam scores in a statistics class are shown in the following table 67 92 76 45 85 70 87 84 67 72 841 85 55 76 84 98 59 93 87 83 ( a ) Complete the following frequency distribution table using 6 classes : 40 -49 , 50- 59 60- 69 70 - 79 , 80- 89 , and 90 - 99 Express the cumulative relative frequency to two decimal places ( Show all work . Just the answer , without supporting work , will receive no credit . ) Cumulative Scores Relative Frequency Relative Frequency Frequency 40 - 49 50 - 59 60- 69 70-79 80 - 89 90 - 99 ( b ) What percentage of the midterm exam scores was at least 80