A regular die has six sides with numbers $1$ to $6$ marked on its sides. If a very large number of throws show the following frequencies of occurrence: $1 \rightarrow 0.167; 2 \rightarrow 0.167; 3\rightarrow 0.152; 4 \rightarrow 0.166; 5\rightarrow 0.168; 6\rightarrow 0.180$. We call this die
- irregular
- biased
- Gaussian
- insufficient