Ecology: Hummingbirds Bill Alther is a zoologist who studies Annas hummingbird (Calypte anna). (Reference: Hummingbirds, K. Long, W. Alther.) Suppose that in a remote part of the Grand Canyon, a random sample of six of these birds was caught, weighed, and released. The weights (in grams) were 3.7 2.9 3.8 4.2 4.8 3.1 The sample mean is Let x be a random variable representing weights of Annas hummingbirds in this part of the Grand Canyon. We assume that x has a normal distribution and It is known that for the population of all Annas hummingbirds, the mean weight is Do the data indicate that the mean weig

Tuesday, February 28 th Chapter 8: Statistical Inference – Confidence Intervals • If I know the population parameters, I can predict the sample statistics • We only know what came out of the box from random sampling and want to make inferences about what’s in the box • One of these inferential procedures is confidence intervals • A reminder o Data are always an imperfect view of the population o What is see (in the data) is not quite the way it (the populatio