安徽省滁州市2023~2024学年高一第一学期期末联考数学.考卷答案

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安徽省滁州市2023~2024学年高一第一学期期末联考数学.考卷答案试卷答案

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Overtheyears,Arecibohasfaceddangeranddamage,butithasalwaysendured.Initslifetime,ithasexperiencedearthquakesandstorms,includingthehurricanethatspoiltPuertoRicoin2017,whichdamagedsomeofthedish.ThetroublebeganinAugust.Ametalsupportcableweighingthousandsofpoundsslippedoutofitssocket(anddroppedsharplyintothecavernous,1,000-foot-wideradiodishinthemiddleofthenight.Thecable,installedinthe1990s,wasconsideredfairlynewforanobservatorythatbeganoperationsin1963,andtheincidentconfusedArecibo'sofficials.Thecable"definitelyshouldnothavefailedinthewayitdid,"AshleyZauderer,theAreciboprogramdirectorattheNationalScienceFoundation,whichownsthetelescope,said.Butearlierthismonth,justdaysbeforeengineerswerescheduledtotrytostabilizethetelescope,anotherpieceofhardwarecamesmashingintothedish.Amaincable,oneoftheoriginalsinstalledwhentheobservatorywasbuilt,hadcracked,causingevenmoredamage.Engineersarenowworkingtoquicklyoutlinedaplantopulldownthetelescopebeforeitcollapsesonitsown.Arecibo'sfailureisadifferentfatethanastronomersareusedto.Hardwareofallsortsagesandbreaks-Hubble,anotherfamedtelescope,isoperatingwithfewerworkingpartsthanitlaunchedwith30yearsago.Butitisunusualtowreckanobservatorybecauseyouhavenootherchoice,andsounexpectedlytoo.32.WhatwillhappentoArecibo?A.Itwillbedestroyed.B.Itwillberebuilt.C.Itwillberepaired.D.Itwillbestabilized.33.Whatdoestheunderlinedword"endured"meaninparagraph2?A.Avoided.B.Survived.C.Endangered.D.Forgotten.34.WhichcanbestexplainAshleyZauderer'smessageinparagraph3?A.Arecibocanberemovedeasily.

分析(Ⅰ)由分层抽样能求出男生、女生分别应抽取多少人.
(Ⅱ)选出的2名同学中有女同学的情况包含两种情况:第1次选出女生第2次选出男生,第一次选出男生第二次选出女生,由此能求出结果.
(Ⅲ)分别求出第一位同学所得数据的平均数、方差和第二位同学所得数据的平均数、方差,由此能判断第二位同学的实验更稳定.

解答(本小题满分12分)
解:(Ⅰ)∵某班有男生33人,女生11人,现按照分层抽样的方法建立一个4人的课外兴趣小组.
∴由分层抽样得:男生应抽取$4×\frac{33}{44}$=3人;女生应抽取$4×\frac{11}{44}$=1人.
(Ⅱ)选出的2名同学中有女同学的概率:
p=$\frac{1}{4}×\frac{3}{3}+\frac{3}{4}×\frac{1}{3}$=0.5.
(Ⅲ)第一位同学所得数据的平均数:
$\overline{{x}_{1}}$=$\frac{1}{5}$(68+70+71+72+74)=71,
第一位同学所得数据的方差:
${{S}_{1}}^{2}$=$\frac{1}{5}$[(68-71)2+(70-71)2+(71-71)2+(71-71)2+(74-71)2]=4,
第二位同学所得数据的平均数:
$\overline{{x}_{2}}$=$\frac{1}{5}$(69+70+70+72+74)=71,
第fg位同学所得数据的方差:
${{S}_{2}}^{2}$=$\frac{1}{5}$[(69-71)2+(70-71)2+(70-71)2+(72-71)2+(74-71)2]=3.2,
∵$\overline{{x}_{1}}=\overline{{x}_{2}}$,${{S}_{1}}^{2}$<${{S}_{2}}^{2}$,∴第二位同学的实验更稳定.

点评本题考查分层抽样的性质,考查概率的求法,考查平均数及方法的应用,是中档题,解题时要注意互斥事件加法公式的合理运用.