题干

司机在开机动车时使用手机是违法行为,会存在严重的安全隐患,危及自己和他人的生命.为了研究司机开车时使用手机的情况,交警部门调查了100名机动车司机,得到以下统计:在55名男性司机中,开车时使用手机的有40人,开车时不使用手机的有15人;在45名女性司机中,开车时使用手机的有20人,开车时不使用手机的有25人.
(Ⅰ)完成下面的2×2列联表,并判断是否有99.5%的把握认为开车时使用手机与司机的性别有关;

开车时使用手机

开车时不使用手机

合计

男性司机人数

女性司机人数

合计

(Ⅱ)以上述的样本数据来估计总体,现交警部门从道路上行驶的大量机动车中随机抽检3辆,记这3辆车中司机为男性且开车时使用手机的车辆数为X,若每次抽检的结果都相互独立,求X的分布列和数学期望E(X).
参考公式与数据: Χ2=
n
(
a
d
b
c
)
2
(
a
+
b
)
(
c
+
d
)
(
a
+
c
)
(
b
+
d
)
,其中n=a+b+c+d.

P(Χ2≥k0

0.150

0.100

0.050

0.025

0.010

0.005

0.001

k0

2.072

2.706

3.841

5.024

6.635

7.879

10.828

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答案(点此获取答案解析)

解:(Ⅰ)填写2×2列联表,如下;

开车时使用手机

同类题5

阅读理解

    What do you think of cats? Some people think very lovely. But not all people love cats. Compared with dogs, cats seem to be very lazy and unfriendly. Besides, cats are not known for acts of selflessness (无私). But maybe we're wrong about them. Don't believe it? Then meet Pippa, a very unusual cat.

    The black-and-white cat was left in a box outside a shop and taken by the British RSPCA to the Jansa family in Whitstable, Kent. They really loved her character (性格) and decided to adopt (收养) it,but they never guessed she'd become a lifesaver.

    Eight-year-old Mia Jansa had diabetes and had become good at testing her blood during the day, as well as having something to eat or drink to bring her blood sugar levels back. But the danger was at night. Mia could easily experience hypoglycemic (低血糖症的) situations when she was asleep, which could cause even death.

    Soon after she was adopted, Pippa went into Mia's bedroom in the middle of the night and woke her up. When the child tested her blood sugar levels, she found they were dangerously low. Ever since, Pippa always visits Mia at night. If she can't get her to wake up, she raises the alarm.

    “Pippa does this of her own accord,” says Mia's mother Laura. “We don't make a request for caring because we don't want to encourage wrong alarms. She gets plenty of hugs. It gives me peace of mind and I know someone else is keeping an eye on Mia.”

    Now the family is so happy that they've chosen to adopt it in the first place.