Now we calculate the frequencies of each class by adding the number of tallies in each. Note that the sum of all class frequencies equals the total number of observations in the sample.

Intervals	Tally	Frequency
65 - 70	\\	2
70 - 75	\\\\ \\	7
75 - 80	\\\\ \\\\ \	16
80 - 85	\\\\ \\\\ \\\\ \\\\ \\\\ \\\\ \	31
85 - 90	\\\\ \\\\ \\\\ \\\\ \\\\	24
90 - 95	\\\\ \\\\ \\\\ \\\	18
95 - 100	\\\\ \\\\ \\\	13
100 - 105	\\\\ \\\\	10
105 - 110	\\\\	5
110 - 115	\\\\	4
Total		n = 130