Allen's hummingbird (selasphorus sasin) has been studied by zoologist bill alther.† suppose a small group of 12 allen's hummingbirds has been under study in arizona. the average weight for these birds is x = 3.15 grams. based on previous studies, we can assume that the weights of allen's hummingbirds have a normal distribution, with σ = 0.28 gram. find an 80% confidence interval for the average weight of allen�s hummingbirds in the study region. what is the margin of error? .109 -1.17 < u < 1.39 (is this correct? ) what conditions are necessary for your calculations? compare your results in the context of this problem. find the sample size necessary for an 80% confidence level with a maximal margin of error e = 0.08 for the mean weight of the hummingbirds. 3.88