Mathematics

The mean of grouped data depends on the sum of all frequencies and the weighted sum of class midpoints. Since you know the mean is 18, you can set up an equation using the formula $\text{Mean} = \frac{\sum f \cdot x}{\sum f}$, where $x$ is each class midpoint and $f$ is frequency. Solve for the unknown frequency, then identify the mode as the class with the highest frequency.

The mean of grouped data depends on the sum of all frequencies and the weighted sum of class midpoints. Since you know the mean is 18, you can set up an equation using the formula $\text{Mean} = \frac{\sum f \cdot x}{\sum f}$, where $x$ is each class midpoint and $f$ is frequency. Solve for the unknown frequency, then identify the mode as the class with the highest frequency.