序号 | 分组睡眠时间 | 组中值 | 频数 (人数) | 频率 |
1 | 4.5 | 80 | ( ) | |
2 | 5.5 | 520 | 0.26 | |
3 | 6.5 | 600 | 0.30 | |
4 | 7.5 | ( ) | ( ) | |
5 | 8.5 | 200 | 0.10 | |
6 | 9.5 | 40 | 0.02 |
A.38辆 | B.28辆 | C.10辆 | D.5辆 |
A.400 | B.600 | C.700 | D.800 |
A. | B. | C. | D. |
A.①② | B.②③ | C.①③ | D.①②③ |
A. | B. | C. | D. |
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