A survey was conducted with high school students in each grade to see how many prefer math or science. Some of the data are shown below. A 6-column table with 3 rows. The first column has no label with entries math, science, total. The second column is labeled 9 with entries blank, 40, 63. The third column is labeled 10 with entries 18, blank, 26. The fourth column is labeled 11 with entries blank, 15, 29. The fifth column is labeled 12 with entries blank, 32, 67. The sixth column is labeled total with entries 90, 95, 185. Which statement is true about the joint frequencies in this table?