Question Three

1. The Research Department at Hisense Limited has established that the companys air conditioners have a life approximate a normal distribution with a mean of 6.5 years and a standard deviation of 2 years. Calculate the probability that:

1. the air conditioners will last more than 8 years. (3 marks)
2. the air conditioners will last more than 5 years but less than 8 years. (4 marks)
3. Hisense Limited would like to establish warranty for the air conditioners such that only 10 % of them will need to be repaired under warranty. What is the cut-off point between those that will receive repairs under warranty and those that will not? (5 marks)
4. Explain any two properties of a normal distribution. (2 marks)

STATISTICS