X~2分布、t分布和f分布地性质及近似计算

1、以下为三个分布的动画演示程序，直接运行：functiondandn(action)%«X2分布、t分布和f分布的性质及近似计算%制作人：幸玮石岩顾秋容%AllRightsReserved%2008.12%无输入参数时进行初始程序，否则调界面参数ifnargin<1,action='initialize'else%看是哪种分布data=get(gco,'UserData');pdflabel=data(4);%图形显示参数，调试时用switchpdflabelcase1xstart=0;%x轴起始点width=120;%x轴范围xdis=30;%x

2、轴刻度间距lenth=0.24;%y轴范围ydis=0.03;%y轴刻度间距speed=0.6;%动画演进速率case2width=6;xdis=3;lenth=0.42;ydis=0.05;speed=0.5;case3width=2;xdis=0.5;lenth=4;ydis=0.4;speed=0.8;endend%初始化模块ifstrcmp(action,'initialize')%数据初始化%分布函数选择pdflabel=0;d=inputdlg('输入分布函数类型：','选择分布函数,1,'x2');ifstrcmp(d,&#

3、39;x2')pdflabel=1;elseifstrcmp(d,'t')pdflabel=2;elseifstrcmp(d,'f')pdflabel=3;end%不符合的输入报错ifpdflabel=0errordlg('分布函数只能选择x2,t与f)returnend%整体用户界面建立，图形显示窗口嵌入figNumber=figure(.'Name','ChangingoftheX2destributionfunction''NumberTitle','off',.'Vi

4、sible','off);axes(.'Units','normalized',.'Visible','off,.'Position',0.060.0650.700.9);%显示初始现实画面switchpdflabelcase1%初始显示参数xstart=0;%x轴起始点width=120;%x轴范围xdis=30;%x轴刻度间距lenth=0.24;%y轴范围ydis=0.03;%y轴刻度间距%画背景图plot(xstartxstart+width,lenthlenth,'b');hold

5、onplot(xstartxstart+width,lenthlenth,'r');plot(xstartxstart+width,lenthlenth,'black');legend('X2分布','正态分布');axis(xstartxstart+width0lenth);gridonset(gca,'XTick',xstart:xdis:xstart+width);set(gca,'YTick',0:ydis:lenth);holdoff%分布函数动画初始参数m=0;n=1;case2widt

6、h=6;xdis=3;lenth=0.42;ydis=0.05;plot(-width-widthwidth,0lenthlenth,'b');holdonplot(-width-widthwidth,0lenthlenth,'r-');plot(-width-widthwidth,0lenthlenth,'black');legend('T分布','正态分布');gridonaxis(-widthwidth0lenth);set(gca,'XTick'，-width:xdis:width);set

7、(gca,'YTick',0:ydis:lenth);holdoffm=0;n=2;otherwisewidth=2;xdis=0.5;lenth=4;ydis=0.4;plot(width,0,'b');holdonplot(width,0,'r');legend('f分布','正态分布');axis(0width0lenth);gridonset(gca,'XTick',0:xdis:width);set(gca,'YTick',0:ydis:lenth);holdoff%f分布

8、输入nn=inputdlg('输入n的值:','获取n',1,'5');n=str2double(n1);ifn<=4errordlg('要使正态逼近式成立n必须大于4!')returnendm=1;end%按钮显示位置top=0.95;left=0.80;btnWid=0.15;btnHt=0.08;spacing=0.02;%“Start”按钮btnNumber=1;labelStr='Start'callbackStr='dandn(''start'')'

9、%显示按钮btnPos=lefttop-btnHtbtnWidbtnHt;uicontrol(.'Style','pushbutton',.'Units','normalized',.'Position',btnPos,.'String',labelStr,.'Callback',callbackStr,.'UserData',btnNumbermnpdflabel);%调用时的句柄参数传递%关闭按钮yPos=top-(btnHt+spacing);uicontrol

10、(.'Style','push',.'Units','normalized',.'Position',leftyPos-btnHtbtnWidbtnHt,.'String','Close',.'Callback','close(gcf)');set(figNumber,'Visible','on');%显示初始图像%“Start”按钮执行程序elseifstrcmp(action,'start')%参数初

11、始化data=get(gco,'UserData');method=data(1);m=data(2);n=data(3);%“Stop”按钮设置，点击开始后替换“Start”按钮btnNumber=2;labelStr='Stop'callbackStr='dandn(''stop'')'top=0.95;left=0.80;btnWid=0.15;btnHt=0.08;btnPos=lefttop-btnHtbtnWidbtnHt;stophld=uicontrol(.'Style','

12、pushbutton',.'Units','normalized',.'Position',btnPos,.'String',labelStr,.'Callback',callbackStr,.'UserData',btnNumbermnpdflabel);%画图程序switchpdflabelcase1while(method=1)%当未点击"Stop”则继续执行%画x2分布密度函数a=n/2;b=2;x=xstart:0.1:xstart+width;y=gampdf(x,a,

13、b);plot(x,y,'b','EraseMode','normal');holdon%画近似正太分布密度函数y1=normpdf(x,n,(2*n)A0.5);plot(x,y1,'r-');%图形参数调节axis(xstartxstart+width0lenth);set(gca,'XTick',xstart:xdis:xstart+width);set(gca,'YTick',0:ydis:lenth);gridon;legend('X2分布','正态分布')

14、;%显示当前ntemp=num2str(floor(n);str=strcat('n=',temp);text(92,0.2,str);%显示当前最大间距dis=num2str(max(abs(y-y1);str=strcat('dis=',dis);text(92,0.187,str);%动画指令drawnow;holdoff;n=n+speed;%看stop是否按下data=get(gco,'UserData');method=data(1);%更新传递参数set(stophld,'Userdata',btnNumbermnp

15、dflabel);endcase2while(method=1)%画t分布密度函数x=-width:0.1:width;y=tpdf(x,n);plot(x,y,'EraseMode','normal');holdon%画近似正太分布密度函数y1=normpdf(x,0,(n/(n-2)A0.5);plot(x,y1,'r-');%图形参数调节axis(-widthwidth0lenth);set(gca,'XTick'，-width:xdis:width);set(gca,'YTick',0:ydis:lenth

16、);gridon;legend('T分布','正态分布');%显示当前ntemp=num2str(floor(n);z=strcat('n=',temp);text(3.3,0.335,z);%显示当前最大间距dis=num2str(max(abs(y-y1);str=strcat('dis=',dis);text(3.3,0.315,str);%动画指令drawnow;holdoff;n=n+speed;%看stop是否按下data=get(gco,'UserData');method=data(1);%更新传递

17、参数set(stophld,'Userdata',btnNumbermnpdflabel);endotherwisewhile(method=1)%画f分布密度函数x=0:0.01:width;y=fpdf(x,m,n);plot(x,y,'EraseMode','normal');holdon%画近似正太分布密度函数y1=normpdf(x,n/(n-2),(2*nA2*(m+n-2)/m/(n-2)A2/(n-4)A0.5);plot(x,y1,'r');%图形参数调节axis(0width0lenth);set(gca,&#

18、39;XTick',0:xdis:width);set(gca,'YTick',0:ydis:lenth);gridon;legend('f分布','正态分布)；%显示当前mtemp1=num2str(floor(m);str=strcat('m=',temp1);text(1.55,3.32,str);%显示当前ntemp2=num2str(floor(n);str=strcat('n=',temp2);text(1.78,3.32,str);%显示当前最大间距dis=num2str(max(abs(y-y1);

19、str=strcat('dis=',dis);text(1.55,3,str);%动画指令drawnow;holdoff;m=m+speed;%看stop是否按下data=get(gco,'UserData');method=data(1);%更新传递参数set(stophld,'Userdata',btnNumbermnpdflabel);endend%“Close”按钮执行程序elseifstrcmp(action,'stop')data=get(gco,'UserData');%读原有传递数据top=0.95

20、;left=0.80;btnWid=0.15;btnHt=0.08;%用acontinue”按钮替代"StopbtnNumber=1;labelStr='Continue'callbackStr='dandn(''continue'')'data(1)=btnNumber;%更新按钮标识btnPos=lefttop-btnHtbtnWidbtnHt;uicontrol(.'Style','pushbutton',.'Units','normalized',.

21、'Position',btnPos,.'String',labelStr,.'Callback',callbackStr,.'UserData',data);%acontinue”按钮执行程序elseifstrcmp(action,'continue')%读取传递数据data=get(gco,'UserData');method=data(1);m=data(2);n=data(3);%用"Stop”按钮替代"continue”btnNumber=2;labelStr='

22、Stop'callbackStr='dandn(''stop'')'top=0.95;left=0.80;btnWid=0.15;btnHt=0.08;btnPos=lefttop-btnHtbtnWidbtnHt;conthld=uicontrol(.'Style','pushbutton',.'Units','normalized',.'Position',btnPos,.'String',labelStr,.'Callback&#

23、39;,callbackStr,.'UserData',btnNumbermnpdflabel);%动画switchpdflabelcase1while(method=1)%画系x2分布密度函数a=n/2;b=2;%画x2分布密度函数x=xstart:0.1:xstart+width;y=gampdf(x,a,b);plot(x,y,'b','EraseMode','normal');holdon%画近似正太分布密度函数y1=normpdf(x,n,(2*n)A0.5);plot(x,y1,'r-');%图形参数调

24、节axis(xstartxstart+width0lenth);set(gca,'XTick',xstart:xdis:xstart+width);set(gca,'YTick',0:ydis:lenth);gridon;legend('X2分布','正态分布');%显示当前ntemp=num2str(floor(n);str=strcat('n=',temp);text(92,0.2,str);%显示当前最大间距dis=num2str(max(abs(y-y1);str=strcat('dis='

25、,dis);text(92,0.187,str);%动画指令drawnow;holdoffn=n+speed;%看stop是否按下data=get(gco,'UserData');method=data(1);%更新传递参数set(conthld,'UserData',btnNumbermnpdflabel);endcase2while(method=1)x=-width:0.1:width;y=tpdf(x,n);plot(x,y,'EraseMode','normal');holdon%画近似正太分布密度函数y1=normpd

26、f(x,0,(n/(n-2)，0.5);plot(x,y1,'r-');%图形参数调节axis(-widthwidth0lenth);set(gca,'XTick'，-width:xdis:width);set(gca,'YTick',0:ydis:lenth);gridon;legend('T分布','正态分布');%显示当前ntemp=num2str(floor(n);z=strcat('n=',temp);text(3.3,0.335,z);%显示当前最大间距dis=num2str(max(abs(y-y1);str=strcat('dis=',dis);text(3.3,0.315,str);%动画指令drawnow;h