(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 |
|
upper limit |
|
margin of error |
|
(b) What conditions are necessary for your calculations? (Select all that apply.)
σ is known
n
is large
uniform distribution of weights
normal distribution of weights
σ is unknown
(c) Interpret your results in the context of this problem.
The probability that this interval contains the true average weight of Allen's hummingbirds is 0.20.
The probability that this interval contains the true average weight of Allen's hummingbirds is 0.80.
We are 20% confident that the true average weight of Allen's hummingbirds falls within this interval.
We are 80% confident that the true average weight of Allen's hummingbirds falls within this interval.
(d) Find the sample size necessary for an 80% confidence level with a maximal margin of error
E= 0.13 for the mean weights of the hummingbirds. (Round up to the nearest whole number.) ______ hummingbirds