Algebra-1

Question Analysis
This question involves calculating the total number of students in a histogram who practice more than 8 hours per week.
The main focus is on identifying intervals that fit the condition ("more than 8 hours") and summing their frequencies.

Key Concept Explanation
Frequencies of Intervals Above a Threshold: For conditions like "more than 8 hours," we include all intervals where the lower bound is greater than 8. This ensures we count only data points that exceed the threshold.

Step-by-Step Solution
Identify intervals with more than 8 hours of practice:
The 9–12 hours interval: Lower bound (9) > 8 → qualifies. Its frequency is 15.
The 13–16 hours interval: Lower bound (13) > 8 → qualifi...