Refer to the image and answer the following questions.

• What is the probability that exactly four telephone lines are busy in a day?
• What is the probability that, at least three telephone lines busy in a day?
• What is the probability that the number of busy telephone lines in a day is at least two but at most four?
• What is the probability that at least one telephone line is busy in a day?
• What is the expected value and variance? Interpret your answer.

Davao City National High School has six telephone lines. For the past months, the probability distribution of the random variable Y which represents the number of busy lines per day is shown in the table below