Please share your Stan program and accompanying data if possible.

When including Stan code in your post it really helps if you make it as readable as possible by using Stan code chunks (```stan) with clear spacing and indentation. For example, use

```
model {
vector[N] mu = alpha + beta * x;
y ~ normal(mu, sigma);
}
```

instead of

model{

vector[N] mu = alpha+beta*x;

y~normal(mu,sigma);

}

To include mathematical notation in your post put LaTeX syntax between two `$`

symbols, e.g.,

p(\theta | y) \propto p(\theta) p(y | \theta).