PROBLEM 1E

The length of life of brand X light bulbs is assumed to be N(μX, 784). The length of life of brand Y light bulbs is assumed to be N(μY, 627) and independent of X. If a random sample of n = 56 brand X light bulbs yielded a mean of

hours and a random sample of size m = 57 brand Y light bulbs yielded a mean of

hours, find a 90% confidence interval for μX − μY.

Lecture 9 Notes (first lecture after midterm) Chapter 10: nature of evolution and habitability Concept of a habitable zone o Although other worlds in the solar system might turn out to have life, there is little doubt that none will have the diversity and abundance of life found on Earth. Why Because we live in a habitable zone o We know that...