60. 解：(1)平均分：87.5分；　　　　 众数：90分；　　 中位数：90分

(2)　　　 七(7)的分数为100分，所以七(7)班为优胜班级.

共50人，从中选出5名，选中的概率为

59. 解：(1)(名)················································································· 2分

答：在这次调查中，一共抽取了50名学生．

(2)(名)·················································································· 1分

补全图形(略)············································································································· 1分

(3)在抽取的学生中，最喜欢滇金丝猴的人数占被抽取人数的百分比为

····································································································································· 1分

由样本估计总体得全校最喜欢滇金线猴的学生约有(名)·················· 1分

答：估计全校最喜欢滇金丝猴的学生约有288名．

58. 解:(1) ①10　 ②100.5　 ③25　 ④1　　　　 (2) 25　 100

57. (1)一般20%.200×(25%+50%)=150(人).

故200名学生中对安全知识了解“较好”、“很好”的总人数为150人.

(2)样本频数的条形统计图如图(2).

(3)从以上信息可看出，全校约有25%的学生对安全知识了解处在“一般”、“较差”层次，说明学校应大力加强安全知识教育，将安全工作落到实处.

0.3×200＝60

∴在这一时噪声声级小于75dB的测量点约有60个.…………………………………9分

56.解:(1)a=8，b=12，c=0.3.(每对一个给1分)…………………………………………3分

(2)略　 (画对一个直方图给1分)…………………………………………………5分

(3)算出样本中噪声声级小于75dB的测量点的频率是0.3…………………………7分

55. 解：(1)；

(2)补画的直方图如图：

(3)41号跑步鞋的销售频率为30%，所以商场计划再进1000双跑步鞋时，41号鞋应进300双左右．

54. (1)根据第一组的频数为15，频率为0.30，

所以这次被抽查的学生人数是

(人)

　第三组的频率为

分数在79.5~89.5之间的人数为50―15―10―18―3＝4人.

频率为.

因此第二列从上至下 两空分别填4、50；第三列从上至下两空分别填0.36、0.08.

(2)总体是300名学生的中考数学成绩.

样本容量为50.

(3)∵∠DOE=∠AOF，∠E=∠AFO=90°，DE=AF，

∴△DOE≌△AOF.

∴S_梯形ABCD＝S_矩形ABGF+ S_矩形CDEG＝0.08+0.36＝0.44.

(4)本题有多个结论，例如，300名初中毕业年级学生数学分数在89.5~99.5的人数最多，约为108人；

或300名初中毕业年级学生数学分数在69.5~79.5的人数最少，约为18人.

53. 解：(1)500＝1000(名)

(2)360⁰＝126⁰

(3)补充正确即可，(1000×15%＝150名)

52. 解：(1)略 ·········································································································· 3分

　　　 (2)略············································································································· 5分

　　　 (3)(人)······································································· 6分

　　　　　 的频率为，大于A、C、D的频率，故这名学生评为B等的可能性最大．　　　 8分