Allen's hummingbird (Selasphorus sasin) has been studied by zoologist Bill Alther. Suppose a small group of 10 Allen's hummingbirds has been under study in Arizona. The average welght 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 o = 0.40 gram.
When finding an 80% confidence interval, what is the critical value for confidence level? (Give your answer to two decimal
places.)
2-
x
(a) Find an 80% confidence interval for the average weights of Allen's hummingbirds in the study region. What is the margin
of error? (Round your answers to two decimal places.)
lower limit
X
upper limit
x
margin of error
X