Allen's hummingbird ( Selasphorus sasin ) has been studied by zoologist Bill Alther. Suppose a small group of 13 Allen's hummingbirds has been under...

Selasphorus sasin13x = 3.15 grams.σ = 0.24 gram.

(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.)

n is large

uniform distribution of weights

σ is unknown

σ is known

normal distribution of weights

(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.     

There is an 80% chance that the interval is one of the intervals containing the true average weight of Allen's hummingbirds in this region.

The probability to the true average weight of Allen's hummingbirds is equal to the sample mean.

There is a 20% chance that the interval is one of the intervals containing the true average weight of Allen's hummingbirds in this region.

(d) Find the sample size necessary for an 80% confidence level with a maximal margin of error  E = 0.10 for the mean weights of the hummingbirds. (Round up to the nearest whole number.) 

 hummingbirds

thirteenx = 5.35 mg/dl.σ = 1.83 mg/dl.(a) Find a 95% confidence interval for the population mean concentration of uric acid in this patient's blood. 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.)

n is large

uniform distribution of uric acid

normal distribution of uric acid

σ is known

σ is unknown

(c) Interpret your results in the context of this problem. 

There is not enough information to make an interpretation.

There is a 95% chance that the confidence interval is one of the intervals containing the population average uric acid level for this patient.     

The probability that this interval contains the true average uric acid level for this patient is 0.05.

There is a 5% chance that the confidence interval is one of the intervals containing the population average uric acid level for this patient.

The probability that this interval contains the true average uric acid level for this patient is 0.95.

(d) Find the sample size necessary for a 95% confidence level with maximal margin of error E = 1.12 for the mean concentration of uric acid in this patient's blood. (Round your answer up to the nearest whole number.) 

 blood tests

40xσ$1.92

(a) Find a 90% confidence interval for the population mean price (per 100 pounds) that farmers in this region get for their watermelon crop. What is the margin of error? (Round your answers to two decimal places.)lower limit    $ upper limit    $ margin of error    $ 

(b) Find the sample size necessary for a 90% confidence level with maximal error of estimate E = 0.29 for the mean price per 100 pounds of watermelon. (Round up to the nearest whole number.)

 farming regions

(c) A farm brings 15 tons of watermelon to market. Find a 90% confidence interval for the population mean cash value of this crop. What is the margin of error? Hint: 1 ton is 2000 pounds. (Round your answers to two decimal places.)lower limit    $ upper limit    $ margin of error    $