给出上述题目的讲解视频---**Question Stem:** 6. 为了了解高三学生的身体状况，抽取了部分男生的体重，将所得的数据整理后，画出了频率分布直方图（如图），已知图中从左到右的前 3 个小组的频率之比为 1 : 2 : 3, 第 2 小组的频数为 12，则抽取的男生人数是 ▲__________. **Options:** *No explicit options (A, B, C, D) are provided.* **Chart Description:** * **Type:** Histogram (频率分布直方图). * **Main Elements:** * **Coordinate Axes:** Vertical axis is labeled "频率/组距" (Frequency/Group Interval), with an upward arrow indicating increasing value. Horizontal axis is labeled "体重" (Weight), with a rightward arrow indicating increasing value. * **Scale/Units:** Horizontal axis is marked with values 50, 55, 60, 65, 70, 75, defining the group intervals [50, 55), [55, 60), [60, 65), [65, 70), [70, 75). Vertical axis has dashed lines indicating values 0.0125 and 0.0375. The tick mark for 0.0125 is below the tick mark for 0.0375. * **Bars:** There are five vertical bars representing the frequency density of each group interval. * Bar for [50, 55) has height approximately 0.0125. * Bar for [55, 60) has height approximately 0.025. * Bar for [60, 65) has height approximately 0.0375. * Bar for [65, 70) has height approximately 0.025. * Bar for [70, 75) has height approximately 0.0125. * **Labels and Annotations:** Text labels include "频率/组距", "体重", and numerical labels 50, 55, 60, 65, 70, 75, 0.0125, 0.0375. The dashed lines correspond to the vertical axis values. **Other Relevant Text:** * The problem states that the ratio of frequencies of the first 3 groups (from left to right) is 1 : 2 : 3. * The problem states that the frequency of the 2nd group is 12. * The blank space and triangle indicate where the answer should be filled in.