Answer Happy

Allen's hummingbird (Selasphorus sasin) has been
studied by zoologist Bill Alther.† Suppose a small group
of 17 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 = 0.20 gram.
When finding an 80% confidence interval, what is the critical
value for confidence level? (Give your answer to two decimal
places.)
zc =
(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.)
uniform distribution of weightsn is large𝜎 is
known𝜎 is unknownnormal distribution of weights
(c)
Interpret your results in the context of this problem.
We are 20% confident that the true average weight of Allen's
hummingbirds falls within this interval.The probability that this
interval contains the true average weight of Allen's hummingbirds
is 0.80. We are 80% confident that the true
average weight of Allen's hummingbirds falls within this
interval.The probability that this interval contains the true
average weight of Allen's hummingbirds is 0.20.
(d)
Which equation is used to find the sample
size n for
estimating 𝜇 when 𝜎 is known?
n =
n =
n =
n =
Find the sample size necessary for an 80% confidence level with
a maximal margin of error E = 0.08 for
the mean weights of the hummingbirds. (Round up to the nearest
whole number.)
hummingbirds