The ages of students in a small primary school ... - JAMB Mathematics 2023 Question

To estimate the mean, we need to find the sum of the products of the class marks and frequencies, and then divide by the sum of frequencies.

\[ \text{Class Interval} \quad | \quad \text{Class Mark} \quad | \quad \text{Frequency (f)} \quad | \quad fx \]
\[ \text{5 - 6} \quad | \quad 5.5 \quad | \quad 29 \quad | \quad 5.5 \times 29 = 159.5 \]
\[ \text{7 - 8} \quad | \quad 7.5 \quad | \quad 40 \quad | \quad 7.5 \times 40 = 300 \]
\[ \text{9 - 10} \quad | \quad 9.5 \quad | \quad 38 \quad | \quad 9.5 \times 38 = 361 \]
\[ \sum f = 107 \quad | \quad \sum fx = 820.5 \]

Now, calculate the mean:

\[ \text{Mean} = \frac{\sum fx}{\sum f} = \frac{820.5}{107} \approx 7.663 \]

Rounded to one decimal place, the mean is approximately 7.7.

Therefore, the correct answer is 7.7.