With reference to Example 4.1, find the variance of the number of television sets with white cords.

Question:

With reference to Example 4.1, find the variance of the number of television sets with white cords.
Example 4.1
A lot of 12 television sets includes 2 with white cords. If 3 of the sets are chosen at random for shipment to a hotel, how many sets with white cords can the shipper expect to send to the hotel?