I'm curious what the phrase "on average" means. Here is an example:

On average, $30\mathrm{\%}$ were further than ___ kilometers away when they had their accident.

Is $30\mathrm{\%}$ a z-score or is it a mean? Transport Canada was investigating accident records to find out how far from their residence people were to when they got into a traffic accident. They took the population of accident records from Ontario and measured the distance the drivers were from home when they had their accident in kilometers (km). The distribution of distances was normally shaped, with $\mu =30$ kilometers and $\sigma =8.0$ kilometers.

On average, $30\mathrm{\%}$ were further than ___ kilometers away when they had their accident.

Is $30\mathrm{\%}$ a z-score or is it a mean? Transport Canada was investigating accident records to find out how far from their residence people were to when they got into a traffic accident. They took the population of accident records from Ontario and measured the distance the drivers were from home when they had their accident in kilometers (km). The distribution of distances was normally shaped, with $\mu =30$ kilometers and $\sigma =8.0$ kilometers.