This is basic statistics, but my prof doesn't teach in a way that's easy for me to understand

"Tire wear is often measured by the number of km until wearout. Below are the "distances until wearout" of a random sample of 15 radial tires of a particular brand. Assume the sample comes from a normal distribution.

a) EStimate the mean number of kilometres until wearout for this brand of tire using a 95% confidence interval. Interpret the interval.

I've found the mean - it's 56. I'm just confused as to how I'm supposed to "interpret" the interval - help would be greatly appreciated, and let me know if you need the list of tire data!

Thanks so very much!