A made-up street has 5 households. They keep 0, 1, 1, 3 and 5 pets…

Step 1. The population mean. $\dfrac{0 + 1 + 1 + 3 + 5}{5} = \dfrac{10}{5} = 2$ pets.

Step 2. All the samples. The ten pair means, in order, are $0.5$, $0.5$, $1$, $1.5$, $2$, $2$, $2.5$, $3$, $3$ and $4$ pets.

Step 3. Their mean. They add up to $20$, so their mean is $\dfrac{20}{10} = 2$ pets, the population mean.

Step 4. Close samples. The means from $1.5$ to $2.5$ are $1.5$, $2$, $2$ and $2.5$. That is $4$ samples.

What it means. Only $4$ of the $10$ samples land close to the truth, yet the samples miss up and down equally, so on average they are right.