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60. 解：(1)平均分：87.5分；　　　　 眾數(shù)：90分；　　 中位數(shù)：90分

(2)　　　 七(7)的分數(shù)為100分，所以七(7)班為優(yōu)勝班級.

共50人，從中選出5名，選中的概率為

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

答：在這次調(diào)查中，一共抽取了50名學生．

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

補全圖形(略)············································································································· 1分

(3)在抽取的學生中，最喜歡滇金絲猴的人數(shù)占被抽取人數(shù)的百分比為

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

由樣本估計總體得全校最喜歡滇金線猴的學生約有(名)·················· 1分

答：估計全校最喜歡滇金絲猴的學生約有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名學生中對安全知識了解“較好”、“很好”的總?cè)藬?shù)為150人.

(2)樣本頻數(shù)的條形統(tǒng)計圖如圖(2).

(3)從以上信息可看出，全校約有25%的學生對安全知識了解處在“一般”、“較差”層次，說明學校應大力加強安全知識教育，將安全工作落到實處.

0.3×200＝60

∴在這一時噪聲聲級小于75dB的測量點約有60個.…………………………………9分

56.解:(1)a=8，b=12，c=0.3.(每對一個給1分)…………………………………………3分

(2)略　 (畫對一個直方圖給1分)…………………………………………………5分

(3)算出樣本中噪聲聲級小于75dB的測量點的頻率是0.3…………………………7分

55. 解：(1)；

(2)補畫的直方圖如圖：

(3)41號跑步鞋的銷售頻率為30%，所以商場計劃再進1000雙跑步鞋時，41號鞋應進300雙左右．

54. (1)根據(jù)第一組的頻數(shù)為15，頻率為0.30，

所以這次被抽查的學生人數(shù)是

(人)

　第三組的頻率為

分數(shù)在79.5~89.5之間的人數(shù)為50―15―10―18―3＝4人.

頻率為.

因此第二列從上至下 兩空分別填4、50；第三列從上至下兩空分別填0.36、0.08.

(2)總體是300名學生的中考數(shù)學成績.

樣本容量為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)本題有多個結(jié)論，例如，300名初中畢業(yè)年級學生數(shù)學分數(shù)在89.5~99.5的人數(shù)最多，約為108人；

或300名初中畢業(yè)年級學生數(shù)學分數(shù)在69.5~79.5的人數(shù)最少，約為18人.

53. 解：(1)500＝1000(名)

(2)360⁰＝126⁰

(3)補充正確即可，(1000×15%＝150名)

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

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

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

　　　　　 的頻率為，大于A、C、D的頻率，故這名學生評為B等的可能性最大．　　　 8分