大连理工大学概率与统计上机作业

第一次上机作业

1

a=normrnd(0,1,[1 1000])

meana=mean(a)

vara=var(a)

hist(a)

 

2.a

b=poissrnd(2,1,100)

meanb=mean(b)

varb=var(b)

hist(b)

 

2.b.c.d

for i = 1:1000

y(i) = mean(poissrnd(2,1,100))

end

for i = 1:1000

x(i) = (y(i)-2)/sqrt(2)

end

meanx = mean(x)

varx = var(x)

hist(x)

第二次上机作业

 

a = unifrnd(5,10,1,1000)

for i = 1:1000

y(i) = 4*a(i)-6;

end

meana = mean(a)

meany = mean(y)

vara = var(a)

vary = var(y)

for i = 1:1000

ay(i) = a(i)*y(i);

end

cov1 = mean(ay)-meana*meany

corr1 = cov1/(sqrt(vara)*sqrt(vary))

for n = 1:3

for i = 1:1000

y(i) = a(i)*exp(2*a(i)^(n-1));

ay(i) = a(i)*y(i);

end

cov(n)=mean(ay)-mean(a)*mean(y);

corr(n) =cov(n)/(sqrt(var(a))*sqrt(var(y)));

end

disp(corr)