最新電大應(yīng)用概率統(tǒng)計試題考試小抄(文件)
【正文】 has a global hub of operation in Chengdu, so the threeday visa has an immediate and positive influence on the pany39。an. Lou held a joint interview with 27 media, including China Daily, the first in a series of interviews entitled Chinese Media Along the Silk Road. The interviews will be in Shaanxi and Gansu provinces and the Xinjiang Uygur autonomous region, as well as Kazakhstan, Uzbekistan and Turkey. The media group held the first interview on Wednesday morning in Xi39。s public security bure au shows some 100 foreign visitors enjoyed the 72hour policy by the end of March, most of them from the United States, the United Kingdom and Germany. Chengdu also reported robust growth in its overall tourist industry last year. Official statistics show that it received some 150 million tourists last year, an increase of 28 percent from 2021. Around million came from abroad, an increase of 12 percent. Total revenue from tourism surpassed 133 billion yuan ($). During his visit to Kazakhstan in September, Chinese President Xi Jinping proposed that China and Central Asia join hands to build a Silk Road economic belt to boost cooperation. The idea has been widely echoed in Central Asian countries, being an encouraging blueprint for Chinese areas along the Silk Road that has linked Asia and Europe for more than 2,000 years. In the next three weeks, China Daily reporters will travel through the belt in China and in Kazakhstan, Uzbekistan and Turkey. They will show the progress and expectations of the countries, businesses and peoples on the route. Shaanxi the start of the ancient Silk Road has positioned itself as the new starting point for the development of the Silk Road Economic Belt, which will strengthen China39。s level of internationalization. The policy will also bring direct economic revenue, Li said. Chengdu has many cultu ral legacies and is also a paradise for panda lovers with the world39。0,xxf x x x????? ? ? ???? 其 它 .， 則 ? ???（ ）． A． ； B． 0 ()f x dx?； C． 0 xdx?； D． ? ? 2 x dx?? ??． 3．設(shè)物件的稱重 ,%95),(~ 過的置信區(qū)間的半長不超的為使 ??NX 則至少應(yīng)稱多少次？（ ）． , ]uu??[ 注 : A． 16； B． 15； C． 4； D． 20． 4．設(shè)隨機變量 X 的概率密度函數(shù)為??? ?? 其他,0 ]1,0[,)( 4 xCxxf ，則常數(shù) C=（ ）． A． 51 ； B． 5； C． 2； D． 12 ． 5．在一個已通過 F檢驗的一元線性回歸方程中，若給定 ??? 1, 00 的則 yxx 的預(yù)測區(qū)間精確表示為（ ）． A． 220000 22( ) ( )11? ? ? ?[ 1 ( 2 ) , 1 ( 2 ) ]x x x xx x x xy t n y t nn L n L??????? ? ? ? ? ? ? ? ? ?； B． 220022( ) ( )11? ? ? ?[ ( 2 ) , ( 2 ) ]x x x xx x x xy t n y t nn L n L????? ? ? ? ? ? ? ?； C．002211? ? ? ?[ ( 2 ) , ( 2 ) ]y t n y t nnn????? ? ? ? ? ?； D．002211? ? ? ?[ , ]yynn??? ? ? ?? ? ? ?． 6．樣本容量為 n 時，樣本方差 2S 是總體方差 2? 的無偏估計量，這是因為（ ）． A． ? ?22ES ?? ； B． ? ? 22ES n?? ； C． 22S ?? ； D． 22S ?? ． 三、解下列各題（ 6 小題，共 48 分） 12 1．設(shè)總體 ? ?~ 0,1XN ， 12, , , nX X X 為簡單隨機樣本，且3 2124( 1)3 iiniiXnFX??????．證明：~ (3, 3)F F n? ． （ 6 分） 2．已知連續(xù)型隨機變量 X 的分布函數(shù)為 0 , 1 。設(shè)測量硬度服從正態(tài)分布， 問在水平 ? = 下 ， 用 此 種 儀 器 測 量 硬 度 所 得 數(shù) 值 是 否 顯 著 偏 低 ？( 0. 05 0. 05 0. 025 0. 025( 4 ) 2 .1 3 2 , ( 5 ) 2 .0 1 5 , ( 4 ) 2 .7 7 6 , ( 5 ) 2 .5 7 1t t t t? ? ? ?) 某廠生產(chǎn)某種產(chǎn)品使用了 3 種不同的催化劑（因素 A）和 4 種不同的原料（因素 B） ，各種搭配都做一次試驗測得成品壓強數(shù)據(jù)。 （ 1）求：甲隊抽到與上屆冠軍隊在同一組的概率； （ 2）求：乙隊抽到與上屆冠軍隊在同一組的概率； （ 3）已知乙隊抽到與上屆冠軍隊在同一組，求：甲隊也是抽到與上屆冠軍隊在 同一組的概率。 （ ） 設(shè) ? ?x? 是服從 標(biāo)準 正態(tài)分布 ? ?0,1N 的隨機變量的分布函數(shù)， X 是 服從正態(tài)分布 ? ?2,N ?? 的隨機變量 ， 則 有 ? ? ? ?21aP X a? ?? ? ? ? ? （ ） 設(shè) 二維隨機變量（ X、 Y）的聯(lián)合概率密度為 ? ?,f x y ，隨機變量 ? ?,Z g X Y? 的數(shù)學(xué)期望存在，則 ? ? ? ? ? ?,xyE Z g x y f x y d x d y? ? ? ?? ?? （ ） 設(shè)總體 X 的分布中的未知參數(shù) ? 的置信度為 1 ?? 的置信區(qū)間為 ? ?12,TT 則有 ? ?12 1P T T??? ? ? ?。 假設(shè)正態(tài)總體的方差未知，對總體均值 ? 作區(qū)間估計。 （ ? ? ? ? ? ? ? ?0 . 0 5 0 . 0 2 5 0 . 0 5
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