# generált adatra N(22,2^2)
nX=50
X=2*rnorm(nX)+22
sigma=2
pk=seq(0.04,0.96,by=0.06)
qX=quantile(X,pk)
qno=qnorm(pk)
plot(qX,qno)
p=c(0.8,0.9,0.95,0.99)
pp=1-0.5*(1-p)
pp=qnorm(pp)
for( i in 1:4 ){
print(c(szint=p[i],
bal=mean(X)-pp[i]*sd(X)/sqrt(nX),
jobb=mean(X)+pp[i]*sd(X)/sqrt(nX)))
}
data(iris)
#head(iris)
X=iris[iris$Species=="setosa","Sepal.Length"]
#hist(X)
#plot(density(X))
summary(X)
nX=length(X)
pk=seq(0.05,0.95,by=0.05)
qX=quantile(X,pk)
qno=qnorm(pk)
plot(qX,qno)
p=c(0.8,0.9,0.95,0.99)
pp=1-0.5*(1-p)
pp=qt(df=nX-1,pp)
for( i in 1:4 ){
print(c(szint=p[i],
bal=mean(X)-pp[i]*sd(X)/sqrt(nX),
jobb=mean(X)+pp[i]*sd(X)/sqrt(nX)))
}
# feladatsor sokasági arány, 1. feladat
k=5
n=100
pk=k/n
alpha=0.1
z=qnorm(1-0.5*alpha)
delta=sqrt(pk*(1-pk))*z/sqrt(n)
print(c(szint=1-alpha,bal=pk-delta,jobb=pk+delta))
# gyufás feladat
x=47:53
p=c(5,10,15,40,15,10,5)/100
valasz1=sum(p[2:4])
print(c(igazi=valasz1))
mu=sum(p*x)
sig2=sum(p*x^2)-mu^2
# print(c(mu=mu, sig2=sig2))
# d=2-vel Csebisev
print(c(csebisev=1-sig2/4))