问题 解答题
江苏省《居住区供配电设施建设标准》规定,住房面积在120m2及以下的居民住宅,用电的基本配置容量(电表的最大功率)应为8千瓦.为了了解某区该类住户家用电器总功率情况,有关部门从中随机调查了50户居民,所得数据(均取整数)如下:
家用电器总功率(单位:千瓦)234567
户数24812168
(1)这50户居民的家用电器总功率的众数是______千瓦,中位数是______千瓦;
(2)若该区这类居民约有2万户,请你估算这2万户居民家用电器总功率的平均值;
(3)若这2万户居民原来用电的基本配置容量都为5千瓦,现市供电部门拟对家用电器总功率已超过5千瓦用户的电表首批增容,改造为8千瓦.请计算该区首批增容的用户约有多少户.
答案

(1)6出现16次,次数最多,则众数是6;将这组数据按从小到大排列为,由于有50个数,第25、26位都是5千瓦,则中位数为5千瓦.

(2)被调查的50户居民家用电器总功率的平均数为5.2千瓦.

于是可以估计,这2万户居民家用电器总功率的平均值约为5.2千瓦.

(3)家用电器总功率已超过5千瓦的用户约有20000×

16+8
50
=9600(户).

所以,首批增容的用户约有9600户.

多项选择题
阅读理解

Diana Jacobs thought her family had a workable plan to pay for college for her 21-year-old twin sons: a combination of savings, income, scholarships, and a modest amount of borrowing. Then her husband lost his job, and the plan fell apart.

“I have two kids in college, and I want to say ‘come home,’ but at the same time I want to provide them with a good education,” says Jacobs.

The Jacobs family did work out a solution: They asked and received more aid form the schools, and each son increased his borrowing to the maximum amount through the federal loan (贷款) program. They will each graduate with $20,000 of debt, but at least they will be able to finish school.

With unemployment rising, financial aid administrators expect to hear more families like the Jacobs. More students are applying for aid, and more families expect to need student loans. College administrators are concerned that they will not have enough aid money to go around.

At the same time, tuition(学费)continues to rise. A report from the National Center for Public Policy and Higher Education found that college tuition and fees increased 439% from 1982 to 2007, while average family income rose just 147%. Student borrowing has more than doubled in the last decade,

“If we go on this way for another 25years, we won’t have an affordable system of higher education,” says Patrick M. Callan, president of the center. “The middle class families have been financing it through debt. They will send kids to college whatever it takes, even if that means a huge amount of debt.”

Financial aid administrators have been having a hard time as many companies decide that student loans are not profitable enough and have stopped making them. The good news, however, is that federal loans account for about three quarters of student borrowing, and the government says that money will flow uninterrupted.

小题1:

According to Paragraph 1, why did the plan of Jacobs family fail?

A.The twins wasted too much money.

B.The father was out of work.

C.Their saving ran out.

D.The family fell apart.小题2:

How did the Jacobs manage to solve their problem?

A.They asked their kids to come home.

B.They borrowed $20,000 from the school.

C.They encouraged their twin sons to do part-time jobs.

D.They got help from the school and the federal government.小题3:

Financial aid administrators believe that _______.

A.more families will face the same problem as the Jacobses

B.the government will receive more letters of complaint

C.college tuition fees will double soon

D.America’s unemployment will fall小题4:

What can we learn about the middle class families from the text?

A.They blamed the government for the tuition increase.

B.Their income remained steady in the last decade.

C.They will try their best to send kids to college.

D.Their debts will be paid off within 25 years.小题5:

According to the last paragraph, the government will      .

A.provide most students will scholarships

B.dismiss some financial aid administrators

C.stop the companies from making student loans

D.go on providing financial support for college students