题干

有2000名网购者在11月11日当天于某购物网站进行网购消费(消费金额不超过1000元),其中有女士1100名,男士900名、该购物网站为优化营销策略,根据性别采用分层抽样的方法从这2000名网购者中抽取200名进行分析,如下表:(消费金额单位:元)
女士消费情况:

消费金额

(0,200)

[200,400)

[400,600)

[600,800)

[800,1000]

人数

10

25

35

30

x

男士消费情况:

消费金额

(0,200)

[200,400)

[400,600)

[600,800)

[800,1000]

人数

15

30

25

y

5

附:

P(K2≥k0

0.10

0.05

0.025

0.010

0.005

k0

2.706

3.841

5.024

6.635

7.879

(K2=
n
(
a
d
b
c
)
2
(
a
+
b
)
(
c
+
d
)
(
a
+
c
)
(
b
+
d
)
,n=a+b+c+d)
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    China is fully prepared to export a full supply chain of high-speed railway technology, according to industry experts.

    China Railway Corp, the national rail operator, said exports of railway equipment and railway construction projects are proceeding well, and breakthroughs are being made in a number of projects overseas.

    Among the projects, the first full-chain commission, the Jakarta to Bandung high-speed railway in Indonesia, which includes technology, design, construction, equipment manufacture, supply of resources, operations management and staff training, has been granted a construction permit and work is proceeding smoothly.

    “China's railways have established a comprehensive and advanced technology system, which is able to provide overseas customers with solutions from many different perspectives, including financing, construction, operations, and research and development,” said Yang Zhongmin, the CRC's deputy chief engineer, who added that China's railway system is competitive in terms of technology and economy of use.

    According to Yang, the nation's railway equipment and infrastructure (基础设施) service businesses have entered markets in Asia, Europe, North America and Africa.

    Last year, Joko Widodo, president of Indonesia, and Malaysian Prime Minister Najib Razak, rode Chinese-made bullet trains.

    Yang Hao, a professor of rail transportation management at Beijing Jiaotong University, said China has a major advantage in that it is able to export a full range of railway technology: “For example, it is inconvenient to import the technology for the signaling system from one country and civil engineering technology from another.”