 Solution

The displayed table has ten categories, including one pooled upper-tail category. With the parameter fixed, no model parameter is fitted and the appropriate reference degrees of freedom are $10-1=9$. The supplied statistic is $15.59$, below the stated five-percent critical value $16.92$. Hence do not reject the specified log-series model at the five-percent level. Using eight degrees of freedom here would incorrectly charge a fitted parameter to a fully specified null.