Fix min_null_pred in the run_qa script (#9067)

examples/question-answering/utils_qa.py

@@ -76,9 +76,7 @@ def postprocess_qa_predictions(
     assert len(predictions) == 2, "`predictions` should be a tuple with two elements (start_logits, end_logits)."
     all_start_logits, all_end_logits = predictions
 
-    assert len(predictions[0]) == len(
-        features
-    ), f"Got {len(predictions[0])} predicitions and {len(features)} features."
+    assert len(predictions[0]) == len(features), f"Got {len(predictions[0])} predictions and {len(features)} features."
 
     # Build a map example to its corresponding features.
     example_id_to_index = {k: i for i, k in enumerate(examples["id"])}
@@ -118,7 +116,7 @@ def postprocess_qa_predictions(
 
             # Update minimum null prediction.
             feature_null_score = start_logits[0] + end_logits[0]
-            if min_null_prediction is None or min_null_prediction["score"] < feature_null_score:
+            if min_null_prediction is None or min_null_prediction["score"] > feature_null_score:
                 min_null_prediction = {
                     "offsets": (0, 0),
                     "score": feature_null_score,