题干

李老师要对初三(1)、(2)班的考试情况进行分析,在两个班里随机抽取了30名学生的考试成绩:87、75、94、60、51、86、73、89、93、67、57、88、82、66、88、88、85、67、91、65、78、89、80、72、78、84、90、64、71、86.

根据上述消息回答下列问题:

(2)估计这两个班级本次考试成绩在80分及80分以上的占____ %;

(4)是否一定能根据这30名学生的成绩估计全区考试成绩?答:____ .

(5)80~90组的平均分为____ ,中位数为____ .

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答案(点此获取答案解析)

53.3,不一定,86.5,86

同类题2

阅读下文,回答问题

白杨礼赞

    ①白杨树实在不是平凡的,我赞美白杨树!

    ②汽车在望不到边际的高原上奔驰,扑入你的视野的,是黄绿错综的一条大毯子。黄的是土,未开垦的荒地,几百万年前由伟大的自然力堆积成功的黄土高原的外壳;绿的呢,是人类劳力战胜自然的成果,是麦田,和风吹送,翻起了一轮一轮的绿波:这时你会真心佩服昔人所造的两个字“麦浪”,若不是妙手偶得,便确是经过锤炼的语言的精华。黄与绿主宰着,无边无垠,坦荡如砥,这时如果不是宛若并肩的远山的连峰提醒了你,你会忘记了汽车是在高原上行驶。这时你涌起来的感想也许是“雄壮”,也许是“伟大”,诸如此类的形容词;然而同时你的眼睛也许觉得有点倦怠,你对当前的“雄壮”或“伟大”闭了眼,而另一种的味儿在你心头潜滋暗长了:“单调”!可不是,单调,有一点儿吧?

    ③然而刹那间,要是你猛抬眼看见了前面远远有一排,不,或者只是三五株,一株,傲然地耸立,像哨兵似的树木的话,那你的恹恹欲睡的情绪又将如何?我那时是惊奇地叫了一声的!

    ④那就是白杨树,西北极普通的一种树,然而实在是不平凡的一种树!

    ⑤那是力争上游的一种树,笔直的干,笔直的枝。它的干通常是丈把高,像加过人工似的,一丈以内绝无旁枝。它所有的丫枝一律向上,而且紧紧靠拢,也像加过人工似的,成为一束,绝不旁逸斜出;它的宽大的叶子也是片片向上,几乎没有斜生的,更不用说倒垂了;它的皮光滑而有银色的晕圈,微微泛出淡青色。这是虽在北方风雪的压迫下却保持着倔强挺立的一种树!哪怕只有碗那样粗细,它却努力向上发展,高到丈许,两丈,参天耸立,不折不挠,对抗着西北风。

    ⑥这就是白杨树,西北极普通的一种树,然而决不是平凡的树!

    ⑦它没有婆娑的姿态,没有屈曲盘旋的虬枝,也许你要说它不美。如果美是专指“婆娑”或“旁逸斜出”之类而言,那么白杨树算不得树中的好女子;但是它伟岸,正直,朴质,严肃,也不缺乏温和,更不用提它的坚强不屈与挺拔,它是树中的伟丈夫!

    ⑧白杨不是平凡的树。它在西北极普遍,不被人重视,就跟北方农民相似;它有极强的生命力,磨折不了,压迫不倒,也跟北方的农民相似。我赞美白杨树,就因为它不但象征了北方的农民,尤其象征了今天我们民族解放斗争中所不可缺的朴质、坚强、力求上进的精神。

    ⑨让那些看不起民众、贱视民众、顽固倒退的人们去赞美那贵族化的楠木,去鄙视这极常见,极易生长的白杨树罢,我要高声赞美白杨树!

(原载《文艺阵地》月刊第6卷第3期,有删改)

链接材料一:

    ①井冈山五百里林海里,最使人难忘的是毛竹。

    ②从远处看,郁郁苍苍,重重叠叠,望不到头。到近处看,有的修直挺拔,好似当年山头的岗哨;有的密密麻麻,好似埋伏在深坳里的奇兵;有却也亭亭玉立,别有一翻神采。

    ③“井冈山的竹子,是革命的竹子!”井冈山人爱这么自豪地说。

    ④有道是:天下竹子数不清,井冈山竹子头一名。

    ⑤是的,当年用自己的血和汗保卫过第一个红色政权的战士们,谁不记得井冈山上的翠竹呢?用它搭过帐篷;用它做过梭镖;用它当罐盛过水,当碗蒸过饭;用它做过扁担和吹火筒;在黄洋界和八面山上,还用它摆过三十里竹钉阵,使多少白匪魂飞魄散,鬼哭狼嚎。如今,早就不再用竹钉当武器了,然而谁又能把它们忘怀呢?

    ⑥井冈山的毛竹,同井冈山的人民一样,坚贞不屈。血雨腥风,毛竹青了又黄,黄了又青,不向残暴低头,不向敌人弯腰;竹叶烧了,还有竹枝,竹枝断了,还有竹鞭,还有深埋地上的竹根。“野火烧不尽,春风吹又生”,一到春天,漫山遍野,向大地显露着无限生机的,依然是那一望无际的翠竹。

    ⑦井冈山的翠竹啊,你是革命的竹子!你永远那么青翠,永远那么挺拔,风吹雨打,从不改色;刀砍火烧,永不低头,你是英雄的井冈山的象征!

(选自袁鹰《井冈翠竹》,有删改)

链接材料二:

    1928年4月,朱德、陈毅率南昌起义残部与***在井冈山会师,两军计万余人,改为中国工农红军第四军。从此,在***、朱德的领导下,井冈山根据地大力发展党组织,深入开展土地革命斗争,巩固扩大红军力量,建立湘赣边界工农政权,成为***领导的革命武装第一个立足点。

(选自百度百科《井冈山精神》)

同类题5

阅读理解

    It was Mother's Day morning last year and I was doing my shopping at our local supermarket with my five-year-old son, Teayson. As we were leaving, we found that only minutes earlier an elderly woman had fallen over at the entrance and had hit her bead on the concrete. Her husband was with her, but there was blood everywhere and the woman was embarrassed and clearly in shock.

    Walking towards the scene, Tenyson became very upset about what had happened to the couple. Ile said to me. “Mums it's not much fun falling over in front of everyone.”

    At the front of the supermarket a charity group had set up a stand selling cooked sausages and flowers to raise funds. Tenyson suggested that we should boy the lady a flower. “It will make her feel better,” he said. I was amazed that he'd come up such a sweet idea. So we went over to the flower seller and asked her if we could buy a flower for the lady to cheer her up. “Just take it,” she replied. “I can't take your money for such a wonderful gesture.”

    By now paramedics(救援人员) had arrived, and were attending the injured woman. As we walked up to her, my son became intimidated by all the blood and medical equipment. He said he was just too scared to go up to her.

    Instead I gave the flower to the woman's husband and told him. “My son was very upset for your wife and wanted to give her this flower to make her feel better.”

    At that, the old man started crying and said, “Thank you so much, you have a wonderful son, Happy Mother's Day to you.”

The man then bent down and gave his wife the flower, telling her who it was from. Though badly hurt and shaken, the old lady looked up at Tenyson with love in her eyes and gave him a little smile.