搜题请搜索小程序“爱下问搜题”
问题 单项选择题

某研究所测定36例结核病患者与28例健康人的脑脊液镁(mmol/L)含量，发现其样本均数分别为 1.04mmol/L和1.28mmol/L，欲进一步研究两样本均数有无差别，应选用的方法是

A．两小样本均数比较的t检验
B．两大样本均数比较的u检验
C．配对计量资料比较的t检验
D．X2检验
E．相关分析

答案

参考答案：A

单项选择题

A total of 4.6 million digital televisions have been sold, and the sales of HDTV sets have quadrupled since last year. Consumers have bought HDTVs to play their DVDs and to have clearer pictures and wide screens. Only a small percentage of the people who have purchased HDTVs, however, have actually ^hooked their TVs up# to receive high-definition television digital signals. Perhaps television viewers are having trouble keeping up with the changes in technology. Even the manufacturers of HDTVs, like Mitsubishi, Thomson Multimedia, Sony, and Samsung seem to have a tough time learning how to make their sets work with the various digital TV formats because little standardization has been required or implemented in the industry.Some of the HDTVs weigh over 200 lbs., and a variety of retailers offer a delivery service to the buyer’’s home to help install the heavy sets. This is known as a white-glove service and usually comes with an extra fee. After HDTV purchasers get their sets home and hook them up, they will still need to work to get the digital signals to their systems. Most of the industry’’s cable providers do not yet offer high-definition programing, and only about 15% of commercial television stations have switched over to even the lowest improved digital pictures. Worse yet, viewers may need to install antenna before they can even get the digital signals to their new HDTV sets. Another frustration for home-theater seekers is that the current HDTV sets allow owners only to watch high-definition programs, not to record them.

Hook up as in "hooked their TVs up" in Paragraph 1 most probably means to________.

A．have a hood over the TV

B．be connected to

C．relate oneself to

D．keep contact with
查看答案
单项选择题

主张“尚同”的组织原则，认为政令必须统一的古代思想家是( )

A．孔子

B．荀子

C．孟子

D．墨子
查看答案