资源描述：
《概数实验前三章答案.docx》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、第一章1（1）>>factorial（9）ans=362880(2)>>nchoosek(10,3)*factorial(3)Ans=720(3)>>nchoosek(10,3)Ans=120(4)>>nchoosek(15,12)Ans=4552.解：假设该同学作文满分，即15分，85道选择题都靠蒙，即每道题做对的概率为四分之一，得60分则通过考试。则该同学通过考试的概率为P。解：>>nchoosek(85,40)*(1/4)^45*(3/4)^40Ans=2.3448e-008即：由此可见，即使该同学作文满分，靠运气通过考试的概率
2、也是如此的低，所以可以认为靠运气不能通过英语四级考试。第二章1(1).>>binopdf(0:20,20,0.25)ans=Columns1through70.00320.02110.06690.13390.18970.20230.1686Columns8through140.11240.06090.02710.00990.00300.00080.0002Columns15through210.00000.00000.00000.00000.00000.00000.0000(2).>>binornd(20,0.25,3,6)ans=9
3、83466634562566474(3).>>binoinv(0.45,20,0.25)ans=5(4).>>x=0:20;y=binopdf(x,20,0.25);>>plot(x,y,'.')>>x=0:0.01:20;y=binocdf(x,20,0.25);>>plot(x,y)2(1).>>poisspdf(0:20,3)ans=Columns1through70.04980.14940.22400.22400.16800.10080.0504Columns8through140.02160.00810.00270.0008
4、0.00020.00010.0000Columns15through210.00000.00000.00000.00000.00000.00000.0000(2).>>poissrnd(3,3,7)ans=033231223243625525524(3).>>poissinv(0.45,3)ans=3(4).>>x=0:10;y=poisspdf(x,3);>>plot(x,y,'.')>>x=0:0.01:10;y=poisscdf(x,3);>>plot(x,y)3(1).>>expcdf(-2:2,4)ans=0000.2212
5、0.3935(2).>>exprnd(4,4,4)ans=0.99123.79973.42880.96961.57020.35103.09823.008620.013527.06831.044613.32342.02893.08494.52706.9519(3).>>expinv(0.45,4)ans=2.3913(4).>>x=0:0.01:10;y=exppdf(x,4);>>plot(x,y)>>x=-1:0.01:10;y=expcdf(x,4);>>plot(x,y)4(1).>>normcdf(-2:5,0,1)ans=C
6、olumns1through70.02280.15870.50000.84130.97720.99871.0000Column81.0000(2).>>normrnd(0,1,3,6)ans=-0.43260.28771.18920.1746-0.58830.1139-1.6656-1.1465-0.0376-0.18672.18321.06680.12531.19090.32730.7258-0.13640.0593(3).>>norminv(0.45,0,1)ans=-0.1257(4).>>x=-10:0.01:10;y1=no
7、rmpdf(x,0,1);y2=normcdf(x,0,1);>>plot(x,y1,x,y2)5.>>norminv(0.99,168,7)ans=184.2844第三章1.>>[M,V]=binostat(10,0.5)M=5V=2.50002.>>[M,V]=poisstat(4)M=4V=43.>>[M,V]=normstat(1,5)M=1V=254.>>symsx;>>f1=2*x+1;f2=4-x;>>Ex=int(x*f1,0,2)+int(x*f2,2,4)Ex=38/3>>Ex2=int(x^2*f1,0,2)+i
8、nt(x^2*f2,2,4);>>Dx=Ex2-Ex^2Dx=-1216/95.>>n=1;>>B=[];>>whilen<=100a=randperm(9);b=sum(a(1:4));B=[B,b];n=n+1;en
