科目:初中數(shù)學 來源: 題型:
| 1 | 6 |
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科目:初中數(shù)學 來源: 題型:
| 女生序號 | ① | ② | ③ | ④ | ⑤ | ⑥ | ⑦ | ⑧ | ⑨ | ⑩ |
| 體重x(kg) | 43 | 48 | 51 | 42 | 41 | 45 | 44 | 46 | 47 | 44 |
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科目:初中數(shù)學 來源: 題型:044
某班45名學生的體重記錄如下(單位:kg):
48 48 42 50 61 44 43 51 46 46
51 46 50 45 52 54 51 57 55 48
49 48 53 48 56 55 57 42 54 49
47 60 51 51 44 41 49 53 52 49
61 58 52 54 50
(1)計算45名學生的平均體重和標準差;
(2)分別選取6名、15名、30名學生體重的一個樣本,計算這三個樣本的平均數(shù)和標準差,最后用總體的平均數(shù)和標準差與它們作比較.你認為隨機抽樣的方法可靠嗎?樣本較大時樣本的估計值與總體是否更接近?
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科目:初中數(shù)學 來源: 題型:044
某年級300名同學的體重如下(單位:kg):
|
49, |
48, |
43, |
52, |
62, |
74, |
43, |
51, |
46, |
47, |
51, |
45, |
50, |
46, |
|
52, |
54, |
50, |
58, |
55, |
58, |
48, |
48, |
53, |
49, |
56, |
55, |
56, |
43, |
|
54, |
68, |
47, |
61, |
51, |
44, |
41, |
49, |
53, |
52, |
49, |
52, |
62, |
58, |
|
52, |
54, |
50, |
47, |
66, |
46, |
47, |
44, |
72, |
55, |
43, |
60, |
51, |
41, |
|
48, |
49, |
43, |
52, |
63, |
44, |
41, |
47, |
48, |
49, |
55, |
53, |
58, |
50, |
|
50, |
43, |
60, |
61, |
52, |
50, |
42, |
44, |
46, |
67, |
47, |
66, |
46, |
47, |
|
69, |
48, |
43, |
50, |
50, |
43, |
46, |
47, |
44, |
42, |
55, |
56, |
55, |
56, |
|
43, |
54, |
49, |
56, |
55, |
56, |
65, |
43, |
60, |
51, |
41, |
48, |
43, |
52, |
|
62, |
46, |
52, |
54, |
50, |
58, |
58, |
52, |
49, |
48, |
43, |
50, |
50, |
47, |
|
44, |
42, |
55, |
63, |
60, |
48, |
43, |
50, |
50, |
43, |
49, |
53, |
52, |
49, |
|
48, |
43, |
50, |
50, |
47, |
44, |
49, |
48, |
43, |
44, |
42, |
55, |
43, |
42, |
|
64, |
46, |
47, |
48, |
43, |
50, |
44, |
41, |
47, |
48, |
49, |
55, |
53, |
58, |
|
55, |
73, |
60, |
51, |
41, |
53, |
49, |
56, |
55, |
56, |
43, |
54, |
44, |
41, |
|
47, |
48, |
49, |
55, |
41, |
48, |
43, |
42, |
44, |
46, |
47, |
42, |
55, |
43, |
|
60, |
68, |
43, |
50, |
48, |
43, |
52, |
62, |
43, |
51, |
46, |
47, |
51, |
45, |
|
49, |
46, |
72, |
54, |
50, |
58, |
47, |
61, |
51, |
44, |
41, |
44, |
41, |
49, |
|
73, |
52, |
49, |
52, |
49, |
56, |
55, |
56, |
43, |
54, |
48, |
47, |
61, |
50, |
|
50, |
43, |
46, |
47, |
44, |
42, |
48, |
43, |
52, |
62, |
55, |
41, |
48, |
43, |
|
42, |
44, |
46, |
47, |
43, |
46, |
67, |
44, |
42, |
44, |
41, |
47, |
48, |
49, |
|
55, |
53, |
72, |
54, |
50, |
58, |
55, |
58, |
49, |
48, |
43, |
52, |
53, |
54, |
|
48, |
47, |
61, |
51, |
44, |
4l, |
49, |
53, |
72, |
49, |
52, |
47, |
66, |
46, |
|
47, |
49, |
48, |
43, |
50, |
49. |
(1)請用計算器或計算機計算總體的平均數(shù)、方差和標準差(精確到0.01),并繪制總體的頻數(shù)分布直方圖;
(2)請用簡單隨機抽樣方法,從上述調(diào)查的數(shù)據(jù)中分別抽取樣本容量為10的兩個樣本,并分別計算這兩個樣本的平均數(shù)、方差和標準差,分別繪制這兩個樣本的頻數(shù)分布直方圖,結(jié)果一致嗎?如果分別抽取樣本容量為20、50的兩個樣本呢?
(3)通過以上的抽樣和計算,你有什么發(fā)現(xiàn)?并與同伴交流.
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