# Unexpected result from r.quantile function

I am watching some old videos of chalkdust on statistics. In one of the videos, the professor calculates quartiles as follows:

But the `r.quantile`

function gives completely different result:

```
sage:
sage: r.quantile([89, 90, 86, 96, 84, 100, 85, 96, 88, 89])
0% 25% 50% 75% 100%
84.0 86.5 89.0 94.5 100.0
sage:
```

Why is that?