Stats, confusing question

Question

Describe how you could use normal distribution to describe how a lightbulb company decides whether or not a lightbulb is defective?

Answer 1

Hi Lily, that's a good question. The normal curve has probabilities under it. These probabilities are usually listed in a normal curve table. You can find these tables in the backs of statistics text books or online. If the company knew the mean and standard deviation of the life of their light bulbs, the company could use a z-score from the normal curve table to get the life of bulbs that had extremly low longevity. Any light bulb that lasted that long or less could be determined to be defective. Basically the bulbs lasted less then what would be expected by chance.