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【简答题】
Passage Three The fridge is considered a necessity. It has been so since the 1960s when packaged food first appeared with the label: ” store it in the refrigerator. ” In my fridgeless Fifties Childhood, I was fed well and healthily. The milkman came daily, the grocer, the butcher, the baker, and the ice0cream man delivered two or three times a week. The Sunday meat would last until Wednesday and surplus ( 剩余 ) bread and milk became all kinds of cakes. Nothing was wasted, and we were never troubled by rotten food. Thirty years on food deliveries have ceased, fresh vegetables are almost unobtainable in the country. The invention of the fridge contributed comparatively little to the art of food preservation. A variety of well-tried techniques already existed --- natural cooling, drying, smoking, salting, sugaring, bottling ... What refrigeration did promote was marketing --- marketing hardware and electricity, marketing soft drinks, marketing dead bodies of animals around the globe in search of a good price. Consequently, most of the world ’ s fridges are to be found, not in the tropics where they might prove useful, but in the wealthy countries with mild temperatures where they are climatically almost unnecessary. Every winter, millions of fridges hum away continuously, and at vast expense, busily maintain an artificially-cooled space inside an artificially-heated house --- while outside, nature provides the desired temperature free of charge. The fridge ’ s effect upon the environment has been evident, while its contribution to human happiness has been insignificant. If you don ’ t believe me, try it yourself. Invest in a food cabinet and turn off your fridge next winter. You may miss the hamburgers, but at least you ’ ll get rid of that terrible hum.
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举一反三
【判断题】交叉锉法一般效率较高,而且可以判断锉面的高低情况,所得表面粗糙度较小,故常用于工件的最后精锉。
A.
正确
B.
错误
【单选题】从正态总体中随机抽取一个 n=10 的随机样本,计算得到 s=7,假定 在α=0.05的显著性水平下,检验假设 得到的结论是( )。
A.
拒绝 H0
B.
接受 H0
C.
可以拒绝也可以接受 H0
D.
可能拒绝也可能接受 H0
【单选题】从正态总体中随机抽取一个n=10的随机样本,计算得到样本均值为17,样本方差为8,要检验假设H0: ,则检验统计量的值为
A.
=8.7
B.
=7.2
C.
=10.38
D.
=19.6
【单选题】视觉分辨法即通过涂面观看自己影像,( )适用于车身的汽车。
A.
涂面着色较深
B.
涂面着色较浅
C.
各种深浅不一
D.
涂面
【单选题】从正态总体中随机抽取一个n=10的随机样本,计算得到 =231.7,s=15.5,假定 =50,在的显著性水平下,检验假设 得到的结论是( )。
A.
拒绝
B.
不拒绝
C.
可以拒绝也可以不拒绝
D.
可能拒绝也可能不拒绝
【单选题】视觉分辨法即通过涂面观看自己影像,( )适用于车身的汽车。
A.
涂面着色较浅
B.
涂面着色较深
C.
各种深浅不一
D.
涂面
【单选题】从某正态总体中随机抽取一个样本,其中n=10,s=6,其样本平均数分布的标准差为(    )。
A.
1.7    
B.
1.9    
C.
2.1    
D.
2.0
【单选题】从正态总体中随机抽取一个n=10的随机样本,计算得到 = 231.7, s=15.5,假定 在 = 0.05 的显著性水平下,检验假设 得到的结论是( )。
A.
拒绝
B.
不 拒绝
C.
可以拒绝也可以不拒绝
D.
可能拒绝也可能不拒绝
【判断题】视觉分辨法即通过涂面观看自己影像,适用于车身颜色较深的汽车。
A.
正确
B.
错误
【单选题】下列属于仓库有效面积的是()。
A.
待检区
B.
走道
C.
备料区
D.
货架
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