Exercise

# Where is the highest accident rate?

It's time to answer the executive's first question: did the accident rate increase from 2016 to 2017? Now that you have the `had_accident`

variable, you can calculate the accident rate by taking the mean of `had_accident`

. Use the appropriate statistical test to see if the accident rate increase is significant. Then, determine which site has the highest accident rate.

Instructions 1/3

**undefined XP**

- Use
`group_by()`

and`summarize()`

to find the mean`accident_rate`

for each year.