Hi！ I dont understand the solution code. I understand the logic how to calculate chi-squared, but not sure I understand all the code.

Screen Link: https://app.dataquest.io/m/99/chi-squared-tests/9/increasing-degrees-of-freedom

What are the `i,obs`

below? `enumerate`

function is to count `observed`

list, so `i`

stands for each element of the list,but what about `obs`

?

Thank you!

```
exp = expected[i]```
My Code: <!--Enclose your code in 3 backticks to format properly-->
```

diffs =

observed = [27816, 3124, 1039, 311, 271]

expected = [26146.5, 3939.9, 944.3, 260.5, 1269.8]

for i, obs in enumerate(observed):

exp = expected[i]

diff = (obs - exp) ** 2 / exp

diffs.append(diff)

race_chisq = sum(diffs)