Question

a light bulb manufacture gaurentees that the mean life of a certain type of bulb is at least 875 hours. A random sample of 40 light bulbs has a mean life of 863 hours with a standard deviation of 50. a=0.04
What is your question?
Work: A random sample of 100 light bulbs has a mean lifetime of 3000 hours. Assume that the population standard deviation of the lifetime is 500 hours. Construct a 95% confidence interval estimate of the mean lifetime


What
percentage of light bulb fail to satisfy to guarantee

Related Questions

a light bulb manufacture claims that the mean life of a certain type of light bulb is more than 750... Write the null and alternative hypotheses. Justify which is the claim. A light bulb manufacturer gua... An electrical firm which manufactures a certain type of bulb wants to estimate its mean life. Assumi... While shopping for light bulbs, which information would describe the efficiency of the bulb? (1 pain...