Algebra-1

Question Analysis
This question tests the understanding of marginal frequencies in a two-way frequency table. The total number of 10th graders, is a marginal frequency.

Key Concept Explanation
Marginal frequencies are the total values in the rows or columns of a two-way frequency table, indicating the total number of observations in a single category of one variable, regardless of the other variable.

Step-by-step Solution
1. Identify the given data: Total number of 9th graders = 30, Total number of 10th graders = 40.
2. Recognize the type: T...