工作就用美篇工作版","guide_search_desc":"海量模板范文,一键做同款 工作就用美篇工作版","img_beautify_switch":0,"ad_free":0,"text_direction":"1","template":{},"container":{},"redirect":{"redirect_type":1,"img_url":false,"link_url":"/wap/downloadpage/backpage","button_bg_color":false,"button_desc":false,"redirect_desc":false},"edit_date_str":"更新于 2020-04-01","current_time":1743787197,"font_name":"","rcmd_meipian":0,"hide_article_link":0,"from_wechat":false,"topk_keywords":[{"name":"中位数","score":0.19572},{"name":"概率","score":0.152744},{"name":"学生","score":0.144806},{"name":"乙组","score":0.122242},{"name":"单价","score":0.121619},{"name":"中考","score":0.121236},{"name":"众数","score":0.120148},{"name":"随机","score":0.092091},{"name":"个球","score":0.090111},{"name":"积分","score":0.083292}],"content":{"article_id":222474166,"content":[{"img_height":720,"img_size":82,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/a6bcecb17e2c4d54c2c1541ab83fbc4c__jpg.heic","img_width":960,"is_origin":false,"source":0,"type":1},{"img_height":442,"img_size":64,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/0f8de0d756d334f899d329253a1edbf4__jpg.heic","img_width":728,"is_origin":false,"source":0,"text":"
初中学段(七、八、九年级)数学知识板块总览思维导图
","type":1},{"img_height":524,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/9dc9d9c01c014ee687c5eab22f7cea5a__jpg.heic","img_width":972,"is_origin":false,"source":0,"type":1},{"source":0,"text":"《2020年河北省数学学科考试说明》
考试形式与试卷结构——与2019年一致
考试采用闭卷笔试形式,全卷总分为120分.考试时间为120分钟.
整个试卷包括卷Ⅰ和卷Ⅱ.卷Ⅰ为选择题,卷Ⅱ为非选择题.
数与代数、图形与几何和统计与概率所占分数的百分比与它们在教学中所占课时的百分比大致相同.数与代数:图形与几何:统计与概率=5:4:1(以上三部分均蕴涵了适量的综合与实践的内容).
试题分选择题、填空题和解答题三种题型.选择题是四选一型单项选择题;填空题只要求直接填写结果,不必写出计算过程或推证过程;解答题包括计算求解题、操作探究题、实验作图题、猜想证明题、实践决策题、综合应用题等,解答应写出文字说明、演算步骤或推证过程(要求直接写出的除外).
数学考试应具有较高的信度、必要的区分度和适当的难度.
试题按其难度分为容易题、中等题和较难题.难度在0.7以上的题为容易题,难度在0.4~0.7之间的题为中等题,难度在0.2~0.4之间的题为较难题,三种试题分值之比约为3:5:2,整套试卷的难度系数为0.65左右.
","type":1},{"img_height":478,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/27007a16ff9f40cbbc5b5bd2420d2175__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"河北省2020年数学学科考试说明——统计概率部分的考试内容和考试要求:
","type":1},{"img_height":608,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/15b7c7d3bc5645c6b484a1bbc579d4b3__jpg.heic","img_width":834,"is_origin":false,"source":0,"type":1},{"img_height":414,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/f57b9664e87e493bae23687b28d41414__jpg.heic","img_width":910,"is_origin":false,"source":0,"text":"2020年《统计和概率》部分中考说明内容思维导图
","type":1},{"source":0,"text":"解题策略:
重点练习两者混搭题目以及练习统计或概率与其他知识混搭题目. 解题中要侧重对图表的理解和认真分析,从获取的信息中找到解决问题的关键.此题属基础题不存在难点,注意计算过程的规范性和准确性.
","type":1},{"source":0,"text":"对于概率类问题特别要注意以下几点:
①注意概率、机会、频率的共同点和不同点。
②注意题目中隐含问题。
③画树状图及其它方法求概率。
④摸球模型题注意放回和不放回。
⑤注意在求概率的问题中寻找替代物,常见的替代物有:球,扑克牌,骰子等。
","type":1},{"img_height":310,"img_size":58,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/ee5036659d892b3ba4ba13babbb89874__jpg.heic","img_width":636,"is_origin":false,"source":0,"text":"概率部分试题关注点和易错点思维导图
","type":1},{"source":0,"text":"河北省近五年中考(2014年——2019年)统计与概率试题赏析:
","type":1},{"img_height":428,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/c8b95108fef04f979f6d57b20fb92868__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"(2019河北中考)
(9分)某球室有三种品牌的4个乒乓球,价格是7,8,9(单位:元)三种.从中随机拿出一个球,已知P(一次拿到8元球)=½.
(1)求这4个球价格的众数;
(2)若甲组已拿走一个7元球训练,乙组准备从剩余3个球中随机拿一个训练.
①所剩的3个球价格的中位数与原来4个球价格的中位数是否相同?并简要说明理由;
②乙组先随机拿出一个球后放回,之后又随机拿一个,用列表法(如图)求乙组两次都拿到8元球的概率.
","type":1},{"img_height":480,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/3e716ddfe859497e8af9fe894fe85172__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"【解答】:(1)∵P(一次拿到8元球)=½,
∴8元球的个数为4×=2(个),按照从小到大的顺序排列为7,8,8,9,
∴这4个球价格的众数为8元;
(2)①所剩的3个球价格的中位数与原来4个球价格的中位数相同;理由如下:
原来4个球的价格按照从小到大的顺序排列为7,8,8,9,
∴原来4个球价格的中位数为=8(元),
所剩的3个球价格为8,8,9,
∴所剩的3个球价格的中位数为8元,
∴所剩的3个球价格的中位数与原来4个球价格的中位数相同;
②列表如图所示:共有9个等可能的结果,乙组两次都拿到8元球的结果有4个,
∴乙组两次都拿到8元球的概率为4/9.
","type":1},{"img_height":434,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/e512005bbdf9409dbaea2a025802e3db__jpg.heic","img_width":834,"is_origin":false,"source":0,"type":1},{"img_height":210,"img_size":50,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/007d025369d4c4e10e090c019a8ca87e__jpg.heic","img_width":532,"is_origin":false,"source":0,"text":"(2018河北中考)
老师随机抽查了本学期学生读课外书册数的情况,绘制成条形图(图 11-1)和不完整的扇形图(图 11-2),其中条形图被墨迹掩盖了一部分.
","type":1},{"source":0,"text":"(1)求条形图中被掩盖的数,并写出册数的中位数;
(2)在所抽查的学生中随机选一人谈读书感想,求选中读书超过5册的学生的概率;
(3)随后又补查了另外几人,得知最少的读了6册,将其与之前的数据合并后,发现册数的中位数没改变,则最多补查了多少 人?
","type":1},{"img_height":570,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/edaa893c25f87834334ff1b3a96a2500__jpg.heic","img_width":778,"is_origin":false,"source":0,"type":1},{"img_height":314,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/5cbd8f65765079873bbac217f2a5f4be__jpg.heic","img_width":748,"is_origin":false,"source":0,"type":1},{"img_height":174,"img_size":24,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/78869e984b8c39cd36f0fdc70268e6c8__jpg.heic","img_width":352,"is_origin":false,"source":0,"text":"(2017河北中考)
编号为号的5名学生进行定点投篮,规定每人投5次,每命中1次记1分,没有命中记0分.如图是根据他们各自的累积得分绘制的条形统计图,之后来了第6号学生也按同样记分规定投了5次,其命中率为 40%.
","type":1},{"source":0,"text":"(1)求第6号学生的积分,并将图增补为这6名学生积分的条形统计图;
(2)在这6名学生中,随机选一名学生,求选上命中率高于50% 的学生的概率;
(3)最后,又来了第7号学生,也按同样记分规定投了5次.这时7名学生积分的众数仍是前6名学生积分的众数,求这个众数,以及第7号学生的积分.
","type":1},{"source":0,"text":"答案:(1)6号的积分为5×40%×1=2(分).
(2)∵这6名学生中。有4名学生的命中率高于50%,
∴P(命中率高于50%的学生)= 2/3.
(3)∵3出现的次数最多,∴这个众数是3.
∵7名学生积分的众数是3,∴7号命中3次或没有命中.
∴7号的积分是3分或0分.
","type":1},{"img_height":536,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/4b0855f556c14d42a6b916d409e26cc7__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"(2017河北中考)
甲、乙两组各有12名学生,组长绘制了本组5月份家庭用水量的统计图表.如图:
甲组12户家庭用水量统计表
","type":1},{"source":0,"text":"比较5月份两组家庭用水量的中位数,下列说法正确的是( B )
A.甲组比乙组大 B.甲、乙两组相同
C.乙组比甲组大 D.无法判断
","type":1},{"img_height":216,"img_size":12,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/8dbad7c62894d0d963a4129e138ce17b__jpg.heic","img_width":320,"is_origin":false,"source":0,"text":"(2016年河北中考)
如图1,一枚质地均匀的正四面体骰子,它有四个面并分别标有数字1,2,3,4如图2,正方形ABCD顶点处各有一个圈.跳圈游戏的规则为:游戏者每掷一次骰子,骰子着地一面上的数字是几,就沿正方形的边顺时针方向连续跳几个边长.
如:若从图A起跳,第一次掷得3,就顺时针连续跳3个边长,落到圈D;若第二次掷得2,就从D开始顺时针连续跳2个边长,落到圈B;……
设游戏者从圈A起跳.
(1)嘉嘉随机掷一次骰子,求落回到圈A的概率P1;
(2)淇淇随机掷两次骰子,用列表法求最后落回到圈 A的概率P2,并指出她与嘉嘉落回到圈A的可能性一样吗?
","type":1},{"img_height":532,"img_size":73,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/eb69e7148b6b975314743b8bf9c7f5fe__jpg.heic","img_width":734,"is_origin":false,"source":0,"type":1},{"source":0,"text":"(2015年河北中考)
某厂生产A,B两种产品,其单价随市场变化而做相应调整,营销人员根据前三次单价变化的情况,绘制了如下统计表及不完整的折线图:
","type":1},{"img_height":324,"img_size":49,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/56c9a889ea6317caa2011d3ceaf3ad0a__jpg.heic","img_width":562,"is_origin":false,"source":0,"type":1},{"img_height":292,"img_size":35,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/6486b0813082b68295070ccda15ae33b__jpg.heic","img_width":466,"is_origin":false,"source":0,"type":1},{"img_height":114,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/7fa16e94e82998874cf0bd860b374880__jpg.heic","img_width":688,"is_origin":false,"source":0,"type":1},{"source":0,"text":"(1)补全图13中B产品单价变化的折线图,B产品第三次的单价比上一次的单价降低了 ( ) %;
(2)求B产品三次单价的方差,并比较哪种产品的单价波动小;
(3)该厂决定第四次调价,A产品的单价仍为6.5元/件,B产品的单价比3元/件上调m%(m>0),使得A产品这四次单价的中位数是B产品四次单价中位数的2倍少1,求m的值。
","type":1},{"img_height":504,"img_size":84,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/72b7cd7ef1aebbf7bbe135b81454b8b3__jpg.heic","img_width":828,"is_origin":false,"source":0,"type":1},{"img_height":322,"img_size":100,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/be31d31bfd9d295883e9e3206a10ab28__jpg.heic","img_width":788,"is_origin":false,"source":0,"type":1},{"img_height":132,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/24d24e8c72ab44d4b6e4c759b4115a90__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"(2014河北中考)
如图①,A,B,C是三个垃圾存放点,点B,C分别位于点A的正北和正东方向,AC=100 m.四人分别测得∠C的度数如表:
他们又调查了各点的垃圾量,并绘制了下列尚不完整的统计图②,③:
(1)求表中∠C度数的平均数x;
(2)求A处的垃圾量,并将图②补充完整;
(3)用(1)中的x作为∠C的度数,要将A处的垃圾沿道路AB都运到B处,已知运送1 kg垃圾每米的费用为0.005元,求运垃圾所需的费用.(注:sin37°=0.6,cos37°=0.8,tan37°=0.75)
","type":1},{"source":0,"text":"答案:
解:(1)x=37°;
(2)A处的垃圾量为80 kg,补全条形统计图如图所示;
(3)∵AB=AC·tan37°=100×0.75=75(m),∴80×75×0.005=30(元),∴运费是30元.
","type":1},{"source":0,"text":"附:冀教版九年级上册第二十三章《数据分析》整章分节思维导图
(谢志芳老师制作)
","type":1},{"img_height":324,"img_size":91,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/92f262cd87a77478e80577140e5b8219__jpg.heic","img_width":640,"is_origin":false,"source":0,"text":"第一节 平均数和加权平均数
","type":1},{"img_height":322,"img_size":92,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/04ccd5e251163870f4e4cf01f11104cc__jpg.heic","img_width":638,"is_origin":false,"source":0,"text":"第二节 众数和中位数
","type":1},{"img_height":338,"img_size":59,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/f0c93883d8386a4f46ef4d32996d757e__jpg.heic","img_width":854,"is_origin":false,"source":0,"text":"第三节 用样本估计总体
","type":1},{"img_height":374,"img_size":80,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/7d9213746080ae57eabe405f92ffcbea__jpg.heic","img_width":852,"is_origin":false,"source":0,"text":"第四节 方差
","type":1},{"img_height":494,"img_size":82,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/06e7f01565d3d497785e0eaa6d4a1ba4__jpg.heic","img_width":852,"is_origin":false,"source":0,"text":"第六节 章节复习
","type":1},{"img_height":538,"img_size":93,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/f8d51958111fa998b9c556613744e95b__jpg.heic","img_width":750,"is_origin":false,"source":0,"text":"学生作品
","type":1},{"img_height":536,"img_size":91,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/2ce9123228d7c12b55d2e2840d637cdc__jpg.heic","img_width":750,"is_origin":false,"source":0,"type":1},{"img_height":534,"img_size":79,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/985ec283e7f0afc5d4acd9a398ddeb6b__jpg.heic","img_width":750,"is_origin":false,"source":0,"type":1},{"img_height":526,"img_size":94,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/d9b7c33464badd7562cf99409dbdc62c__jpg.heic","img_width":750,"is_origin":false,"source":0,"type":1},{"img_height":536,"img_size":95,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/508fd68844aff7d231df14b4b91cadc3__jpg.heic","img_width":750,"is_origin":false,"source":0,"type":1},{"img_height":552,"img_size":78,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/85dc6604bf12968ea983b718bf295952__jpg.heic","img_width":750,"is_origin":false,"source":0,"text":"更多内容请关注微信公众号,您的支持与关注是我们努力前行的动力!
","type":1}]},"ext":{"id":135506102,"article_id":222474166,"ip":"123.196.173.221","origin_status":0,"edit_from":0,"client_type":2,"password_v2":"","uv":1,"font_id":0,"title_style":"","rich_text_title":"","gift_switch":1,"deleted_at":0,"recycle_expired_at":0,"share_with_nickname":0,"enable_watermark":0,"music_id":0,"music_source":-1,"_auto_update_time":"2024-12-14 21:04:03"},"extend":{"article_id":222474166,"enable_download":1}},"author":{"id":"3207061","nickname":"鹿泉区实验初级中学党总支","head_img_url":"https://ss-mpvolc.meipian.me/users/3207061/94d5522e84904bd6a5294d76c73b8f57.jpg","column_visit":321,"signature":"谢志芳","favorite_count":1,"follow_count":63,"follower_count":133,"famous_type":0,"autoplay_music":1,"text_preference":2,"client_type":1,"reward_word":"如果喜欢我的作品,请打赏鼓励哦!","member_type":0,"wechat_id":"ojq1ttz_h4zJsJxUd_TW7kDC5nK4","country":"中国","province":"河北","city":"石家","career":9,"birthday":19731002,"gender":0,"reg_time":1468628298,"e_id":"","bedge_img":"","label_img":"","review_level":1,"enable_reward_switch":false,"enable_water_mark_switch":0,"plainNickname":"鹿泉区实验初级中学党总支","member_status":0,"member_img":"","ext":null,"phone_num":"139****3673","head_attach_img":null,"badge":null,"onlive":false,"qualification":null,"biz_info":{"is_biz_user":false,"share_domains":[]},"headwear":{"icon":"","animation":"","config":{},"param":{}},"cover_img_url":"","weibo_id":"","vwen_id":"88a8d97f4fcca3546b9f5a16b4544696","im_id":"aa90e6a68937852af9b7a78ba1b59d3d","yx_im_token":"","last_visit_time":1718593870,"ip_address":"121.28.15.121","device_id":"d957198df3c5606e:02:00:00:00:00:00","reviewer":0,"review_time":0,"account_state":0,"balance":216,"last_contribution_time":0,"member_expire_time":0,"member_qq_group":0,"web_has_login":0,"longtitude":"114.3107600","latitude":"38.0888440","last_client_type":0,"level":0,"province_user":"河北","city_user":"石家庄","user_id":3207061,"qq_id":"","apple_id":"","badge_img_url":"","reward_url":"https://www.meipian.cn/wap/reward/view/index.html?mask_id=2u7bdhgc&author_user_id=3207061&article_title=%E9%B9%BF%E6%B3%89%E5%8C%BA%E8%B0%A2%E5%BF%97%E8%8A%B3%E5%88%9D%E4%B8%AD%E6%95%B0%E5%AD%A6%E5%90%8D%E5%B8%88%E5%B7%A5%E4%BD%9C%E5%AE%A4%E5%85%AC%E7%9B%8A%E8%AE%B2%E5%A0%82%E7%AC%AC%E4%B8%89%E5%8D%81%E4%B8%89%E8%AE%B2%EF%BC%9A%E6%80%9D%E7%BB%B4%E5%AF%BC%E5%9B%BE%E5%8A%A9%E5%8A%9B%E6%95%B0%E5%AD%A6%E5%AD%A6%E4%B9%A0%EF%BC%88%E5%8D%81%E5%9B%9B%EF%BC%89%E2%80%94%E2%80%94%E4%B8%AD%E8%80%83%E6%95%B0%E5%AD%A6%E4%B8%93%E9%A2%98%EF%BC%9A%E7%BB%9F%E8%AE%A1%E4%B8%8E%E6%A6%82%E7%8E%87","memo_name":""},"content":[{"img_height":720,"img_size":82,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/a6bcecb17e2c4d54c2c1541ab83fbc4c__jpg.heic","img_width":960,"is_origin":false,"source":0,"type":1},{"img_height":442,"img_size":64,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/0f8de0d756d334f899d329253a1edbf4__jpg.heic","img_width":728,"is_origin":false,"source":0,"text":"初中学段(七、八、九年级)数学知识板块总览思维导图
","type":1},{"img_height":524,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/9dc9d9c01c014ee687c5eab22f7cea5a__jpg.heic","img_width":972,"is_origin":false,"source":0,"type":1},{"source":0,"text":"《2020年河北省数学学科考试说明》
考试形式与试卷结构——与2019年一致
考试采用闭卷笔试形式,全卷总分为120分.考试时间为120分钟.
整个试卷包括卷Ⅰ和卷Ⅱ.卷Ⅰ为选择题,卷Ⅱ为非选择题.
数与代数、图形与几何和统计与概率所占分数的百分比与它们在教学中所占课时的百分比大致相同.数与代数:图形与几何:统计与概率=5:4:1(以上三部分均蕴涵了适量的综合与实践的内容).
试题分选择题、填空题和解答题三种题型.选择题是四选一型单项选择题;填空题只要求直接填写结果,不必写出计算过程或推证过程;解答题包括计算求解题、操作探究题、实验作图题、猜想证明题、实践决策题、综合应用题等,解答应写出文字说明、演算步骤或推证过程(要求直接写出的除外).
数学考试应具有较高的信度、必要的区分度和适当的难度.
试题按其难度分为容易题、中等题和较难题.难度在0.7以上的题为容易题,难度在0.4~0.7之间的题为中等题,难度在0.2~0.4之间的题为较难题,三种试题分值之比约为3:5:2,整套试卷的难度系数为0.65左右.
","type":1},{"img_height":478,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/27007a16ff9f40cbbc5b5bd2420d2175__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"河北省2020年数学学科考试说明——统计概率部分的考试内容和考试要求:
","type":1},{"img_height":608,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/15b7c7d3bc5645c6b484a1bbc579d4b3__jpg.heic","img_width":834,"is_origin":false,"source":0,"type":1},{"img_height":414,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/f57b9664e87e493bae23687b28d41414__jpg.heic","img_width":910,"is_origin":false,"source":0,"text":"2020年《统计和概率》部分中考说明内容思维导图
","type":1},{"source":0,"text":"解题策略:
重点练习两者混搭题目以及练习统计或概率与其他知识混搭题目. 解题中要侧重对图表的理解和认真分析,从获取的信息中找到解决问题的关键.此题属基础题不存在难点,注意计算过程的规范性和准确性.
","type":1},{"source":0,"text":"对于概率类问题特别要注意以下几点:
①注意概率、机会、频率的共同点和不同点。
②注意题目中隐含问题。
③画树状图及其它方法求概率。
④摸球模型题注意放回和不放回。
⑤注意在求概率的问题中寻找替代物,常见的替代物有:球,扑克牌,骰子等。
","type":1},{"img_height":310,"img_size":58,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/ee5036659d892b3ba4ba13babbb89874__jpg.heic","img_width":636,"is_origin":false,"source":0,"text":"概率部分试题关注点和易错点思维导图
","type":1},{"source":0,"text":"河北省近五年中考(2014年——2019年)统计与概率试题赏析:
","type":1},{"img_height":428,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/c8b95108fef04f979f6d57b20fb92868__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"(2019河北中考)
(9分)某球室有三种品牌的4个乒乓球,价格是7,8,9(单位:元)三种.从中随机拿出一个球,已知P(一次拿到8元球)=½.
(1)求这4个球价格的众数;
(2)若甲组已拿走一个7元球训练,乙组准备从剩余3个球中随机拿一个训练.
①所剩的3个球价格的中位数与原来4个球价格的中位数是否相同?并简要说明理由;
②乙组先随机拿出一个球后放回,之后又随机拿一个,用列表法(如图)求乙组两次都拿到8元球的概率.
","type":1},{"img_height":480,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/3e716ddfe859497e8af9fe894fe85172__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"【解答】:(1)∵P(一次拿到8元球)=½,
∴8元球的个数为4×=2(个),按照从小到大的顺序排列为7,8,8,9,
∴这4个球价格的众数为8元;
(2)①所剩的3个球价格的中位数与原来4个球价格的中位数相同;理由如下:
原来4个球的价格按照从小到大的顺序排列为7,8,8,9,
∴原来4个球价格的中位数为=8(元),
所剩的3个球价格为8,8,9,
∴所剩的3个球价格的中位数为8元,
∴所剩的3个球价格的中位数与原来4个球价格的中位数相同;
②列表如图所示:共有9个等可能的结果,乙组两次都拿到8元球的结果有4个,
∴乙组两次都拿到8元球的概率为4/9.
","type":1},{"img_height":434,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/e512005bbdf9409dbaea2a025802e3db__jpg.heic","img_width":834,"is_origin":false,"source":0,"type":1},{"img_height":210,"img_size":50,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/007d025369d4c4e10e090c019a8ca87e__jpg.heic","img_width":532,"is_origin":false,"source":0,"text":"(2018河北中考)
老师随机抽查了本学期学生读课外书册数的情况,绘制成条形图(图 11-1)和不完整的扇形图(图 11-2),其中条形图被墨迹掩盖了一部分.
","type":1},{"source":0,"text":"(1)求条形图中被掩盖的数,并写出册数的中位数;
(2)在所抽查的学生中随机选一人谈读书感想,求选中读书超过5册的学生的概率;
(3)随后又补查了另外几人,得知最少的读了6册,将其与之前的数据合并后,发现册数的中位数没改变,则最多补查了多少 人?
","type":1},{"img_height":570,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/edaa893c25f87834334ff1b3a96a2500__jpg.heic","img_width":778,"is_origin":false,"source":0,"type":1},{"img_height":314,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/5cbd8f65765079873bbac217f2a5f4be__jpg.heic","img_width":748,"is_origin":false,"source":0,"type":1},{"img_height":174,"img_size":24,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/78869e984b8c39cd36f0fdc70268e6c8__jpg.heic","img_width":352,"is_origin":false,"source":0,"text":"(2017河北中考)
编号为号的5名学生进行定点投篮,规定每人投5次,每命中1次记1分,没有命中记0分.如图是根据他们各自的累积得分绘制的条形统计图,之后来了第6号学生也按同样记分规定投了5次,其命中率为 40%.
","type":1},{"source":0,"text":"(1)求第6号学生的积分,并将图增补为这6名学生积分的条形统计图;
(2)在这6名学生中,随机选一名学生,求选上命中率高于50% 的学生的概率;
(3)最后,又来了第7号学生,也按同样记分规定投了5次.这时7名学生积分的众数仍是前6名学生积分的众数,求这个众数,以及第7号学生的积分.
","type":1},{"source":0,"text":"答案:(1)6号的积分为5×40%×1=2(分).
(2)∵这6名学生中。有4名学生的命中率高于50%,
∴P(命中率高于50%的学生)= 2/3.
(3)∵3出现的次数最多,∴这个众数是3.
∵7名学生积分的众数是3,∴7号命中3次或没有命中.
∴7号的积分是3分或0分.
","type":1},{"img_height":536,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/4b0855f556c14d42a6b916d409e26cc7__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"(2017河北中考)
甲、乙两组各有12名学生,组长绘制了本组5月份家庭用水量的统计图表.如图:
甲组12户家庭用水量统计表
","type":1},{"source":0,"text":"比较5月份两组家庭用水量的中位数,下列说法正确的是( B )
A.甲组比乙组大 B.甲、乙两组相同
C.乙组比甲组大 D.无法判断
","type":1},{"img_height":216,"img_size":12,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/8dbad7c62894d0d963a4129e138ce17b__jpg.heic","img_width":320,"is_origin":false,"source":0,"text":"(2016年河北中考)
如图1,一枚质地均匀的正四面体骰子,它有四个面并分别标有数字1,2,3,4如图2,正方形ABCD顶点处各有一个圈.跳圈游戏的规则为:游戏者每掷一次骰子,骰子着地一面上的数字是几,就沿正方形的边顺时针方向连续跳几个边长.
如:若从图A起跳,第一次掷得3,就顺时针连续跳3个边长,落到圈D;若第二次掷得2,就从D开始顺时针连续跳2个边长,落到圈B;……
设游戏者从圈A起跳.
(1)嘉嘉随机掷一次骰子,求落回到圈A的概率P1;
(2)淇淇随机掷两次骰子,用列表法求最后落回到圈 A的概率P2,并指出她与嘉嘉落回到圈A的可能性一样吗?
","type":1},{"img_height":532,"img_size":73,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/eb69e7148b6b975314743b8bf9c7f5fe__jpg.heic","img_width":734,"is_origin":false,"source":0,"type":1},{"source":0,"text":"(2015年河北中考)
某厂生产A,B两种产品,其单价随市场变化而做相应调整,营销人员根据前三次单价变化的情况,绘制了如下统计表及不完整的折线图:
","type":1},{"img_height":324,"img_size":49,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/56c9a889ea6317caa2011d3ceaf3ad0a__jpg.heic","img_width":562,"is_origin":false,"source":0,"type":1},{"img_height":292,"img_size":35,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/6486b0813082b68295070ccda15ae33b__jpg.heic","img_width":466,"is_origin":false,"source":0,"type":1},{"img_height":114,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/7fa16e94e82998874cf0bd860b374880__jpg.heic","img_width":688,"is_origin":false,"source":0,"type":1},{"source":0,"text":"(1)补全图13中B产品单价变化的折线图,B产品第三次的单价比上一次的单价降低了 ( ) %;
(2)求B产品三次单价的方差,并比较哪种产品的单价波动小;
(3)该厂决定第四次调价,A产品的单价仍为6.5元/件,B产品的单价比3元/件上调m%(m>0),使得A产品这四次单价的中位数是B产品四次单价中位数的2倍少1,求m的值。
","type":1},{"img_height":504,"img_size":84,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/72b7cd7ef1aebbf7bbe135b81454b8b3__jpg.heic","img_width":828,"is_origin":false,"source":0,"type":1},{"img_height":322,"img_size":100,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/be31d31bfd9d295883e9e3206a10ab28__jpg.heic","img_width":788,"is_origin":false,"source":0,"type":1},{"img_height":132,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/24d24e8c72ab44d4b6e4c759b4115a90__jpg.heic","img_width":834,"is_origin":false,"source":0,"text":"(2014河北中考)
如图①,A,B,C是三个垃圾存放点,点B,C分别位于点A的正北和正东方向,AC=100 m.四人分别测得∠C的度数如表:
他们又调查了各点的垃圾量,并绘制了下列尚不完整的统计图②,③:
(1)求表中∠C度数的平均数x;
(2)求A处的垃圾量,并将图②补充完整;
(3)用(1)中的x作为∠C的度数,要将A处的垃圾沿道路AB都运到B处,已知运送1 kg垃圾每米的费用为0.005元,求运垃圾所需的费用.(注:sin37°=0.6,cos37°=0.8,tan37°=0.75)
","type":1},{"source":0,"text":"答案:
解:(1)x=37°;
(2)A处的垃圾量为80 kg,补全条形统计图如图所示;
(3)∵AB=AC·tan37°=100×0.75=75(m),∴80×75×0.005=30(元),∴运费是30元.
","type":1},{"source":0,"text":"附:冀教版九年级上册第二十三章《数据分析》整章分节思维导图
(谢志芳老师制作)
","type":1},{"img_height":324,"img_size":91,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/92f262cd87a77478e80577140e5b8219__jpg.heic","img_width":640,"is_origin":false,"source":0,"text":"第一节 平均数和加权平均数
","type":1},{"img_height":322,"img_size":92,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/04ccd5e251163870f4e4cf01f11104cc__jpg.heic","img_width":638,"is_origin":false,"source":0,"text":"第二节 众数和中位数
","type":1},{"img_height":338,"img_size":59,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/f0c93883d8386a4f46ef4d32996d757e__jpg.heic","img_width":854,"is_origin":false,"source":0,"text":"第三节 用样本估计总体
","type":1},{"img_height":374,"img_size":80,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/7d9213746080ae57eabe405f92ffcbea__jpg.heic","img_width":852,"is_origin":false,"source":0,"text":"第四节 方差
","type":1},{"img_height":494,"img_size":82,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/06e7f01565d3d497785e0eaa6d4a1ba4__jpg.heic","img_width":852,"is_origin":false,"source":0,"text":"第六节 章节复习
","type":1},{"img_height":538,"img_size":93,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/f8d51958111fa998b9c556613744e95b__jpg.heic","img_width":750,"is_origin":false,"source":0,"text":"学生作品
","type":1},{"img_height":536,"img_size":91,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/2ce9123228d7c12b55d2e2840d637cdc__jpg.heic","img_width":750,"is_origin":false,"source":0,"type":1},{"img_height":534,"img_size":79,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/985ec283e7f0afc5d4acd9a398ddeb6b__jpg.heic","img_width":750,"is_origin":false,"source":0,"type":1},{"img_height":526,"img_size":94,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/d9b7c33464badd7562cf99409dbdc62c__jpg.heic","img_width":750,"is_origin":false,"source":0,"type":1},{"img_height":536,"img_size":95,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/508fd68844aff7d231df14b4b91cadc3__jpg.heic","img_width":750,"is_origin":false,"source":0,"type":1},{"img_height":552,"img_size":78,"img_url":"https://ss-mpvolc.meipian.me/users/3207061/85dc6604bf12968ea983b718bf295952__jpg.heic","img_width":750,"is_origin":false,"source":0,"text":"更多内容请关注微信公众号,您的支持与关注是我们努力前行的动力!
","type":1}],"mark":0,"gift":{"icon":"https://ss2.meipian.me/app/article_gift_flower_icon_v2.png","amount":0,"mix_icon":"","mix_persent":0,"display":1},"topic":{"has_vote":0,"vote_rank":0,"vote_count":0},"visitor":{"is_share":false,"visitor_id":0,"visitor_user_id":null,"from":null,"channel":null,"theme":null,"in_app":false,"from_web":false,"self_view":false,"timestamp":null,"sign":null,"is_from_app_launch":null,"show_praise":null,"praised":null,"wechat_sign":null,"token":null,"password_v2":null,"visitor_open_id":null,"share_depth":"","visitor_union_id":null,"ua_source":"web","mpuuid":"","isFan":0,"relation_type":0,"member_status":0,"member_img":"","head_attach_img":"","headwear":null,"request":{"attributes":{},"request":{},"query":{},"server":{},"files":{},"cookies":{},"headers":{}},"is_new_guest":0,"first_share_uid":0,"risk_cheat_info":"","is_cheat_risk":false,"page_visit_id":"PC_132242298567f014bd258ba5.49837066","is_good":null,"auth_url":null,"from_auth_callback":0},"watermark":"?watermark/3/image/aHR0cDovL3N0YXRpYzItc3JjLml2d2VuLmNvbS9sb2dvd2F0ZXIucG5n/dy/50/text/QCDpub_ms4nljLrlrp7pqozliJ3nuqfkuK3lrablhZrmgLvmlK8=/fontsize/320/dx/10/dy/30/fill/I0ZGRkZGRg==/text/576O56-H5Y-377yaMzIwNzA2MQ==/fontsize/320/dx/10/dy/10/fill/I0ZGRkZGRg=="}; var detail = ARTICLE_DETAIL; window.model = { detail: ARTICLE_DETAIL }