#random cosine wave model

# Y_t=cos(2*pi*(t/12+Phi)) # Phi=random phase ~U(0,1)
n=120
t=1:120
Phi=runif(1);Phi
Y=cos(2*pi*(t/12+Phi))
plot(Y,type='o')
nrepl=50
for (i in 1:nrepl) {
Phi=runif(1);Phi
Y=cos(2*pi*(t/12+Phi))
lines(y=Y,x=t,type='o')
}