Root Mean Squared Error (RMSE)
Submissions are scored on the root mean squared error. RMSE is defined as:
\[\textrm{RMSE} = \sqrt{\frac{1}{n} \sum_{i=1}^{n} (y_i - \hat{y}_i)^2},\]
where y hat is the predicted value and y is the original value.
## Submission File

For each `item_id` in the test set, you must predict a probability for the `deal_probability`. Your predictions must be in the range [0, 1]. The submission file should contain a header and have the following format:

    item_id,deal_probability
    2,0
    5,0
    6,0
    etc.