421. The plant produces an average of 70% of products with a quality mark. Find the probability that in a batch of 1000 items the number of products with a quality mark is between 650 and 750.421. The plant produces an average of 70% of products with a quality mark. Find the probability that in a batch of 1000 items the number of products with a quality mark is between 650 and 750.

Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)