Question 1.170

5. An electrical company has developed a new form of light bulb that it claims lasts longer than current models. The company has 1 million bulbs in its inventory. Consider the population average lifetime.

  1. What is the only way to find out the population average lifetime of the 1 million bulbs in the inventory?
  2. Suppose someone who worked for you wrote you a memo suggesting that it was crucial to know the exact value of the population average lifetime of all 1 million new light bulbs. How would you respond? What might you suggest instead?

1.99.5

(a) Turn on all 1 million light bulbs, leave them all on until they burn out, compute the average of all bulb lifetimes. (b) Use the average lifetime of a sample to estimate the average lifetime of the population.