Allen's hummingbird (Selasphorus sasin) has been studied by zoologist Bill Alther.† Suppose a small group of 20 Allen's hummingbirds has been under study in Arizona. The average weight for these birds is x = 3.70 grams. Based on previous studies, we can assume that the weights of Allen's hummingbirds have a normal distribution, with σ = 0.32 gram. When finding an 86% confidence interval, what is the critical value for confidence level? (Give your answer to two decimal places.) zc =  (a) Find an 86% 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   Find the minimum sample size necessary for an 86% confidence level with a maximal margin of error E = 0.15 for the mean weights of the hummingbirds. (Round your answer to a whole number.)  hummingbirds

Allen's hummingbird (Selasphorus sasin) has been studied by zoologist Bill Alther.† Suppose a small group of 16 Allen's hummingbirds has been under study in Arizona. The average weight for these birds is x = 3.10 grams. Based on previous studies, we can assume that the weights of Allen's hummingbirds have a normal distribution, with σ = 0.30 gram.   When finding an 82% confidence interval, what is the critical value for confidence level? (Give your answer to two decimal places.) zc =  (a) Find an 82% 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.) normal distribution of weights σ is unknown σ is known uniform distribution of weights n is large (c) Interpret your results in the context of this problem. We are 82% confident that the…

A researcher constructs a confidence interval using the value z*=1.44. What confidence level does their interval have

A sample of 49 sudden infant death syndrome (SIDS) cases had a mean birth weight of 2998 g. Based on other births in the county, we will assume σ = 800 g. Calculate the 95% confidence interval for the mean birth weight of SIDS cases in the county. Interpret your results.

One method for measuring air pollution is to measure the concentration of carbon monoxide, or CO, in the air. Suppose Nina, an environmental scientist, wishes to estimate the CO concentration in Zagreb, Croatia. She randomly selects 45 locations throughout the city measures the CO concentration at each location. Based on her 45 samples, she computes the margin of error for a 95% t-confidence interval for the mean concentration of CO in Zagreb, in µg/m³, to be 4.28. What would happen to the margin of error if Nina decreases the confidence level to 90%? Nina increases the confidence level to 99%? Nina decreases the sample size to 33 locations? Nina increases the sample size to 65 locations? Answer Bank Increase Stay the same Decrease

In a clinical trial, 50 patients who received a new medication are randomly selected. It was found that 10 of them suffered serious side effects from this new medication. Let p denote the population proportion of patients suffered serious side effects from this new medication. Find a point estimate for p. Construct a 95% confidence interval for p: ( ). (Write down all the digits you have from calculator)

Suppose that a garage samples 21 customers. They find the average time for there oil change is 4,305 miles. Find a 90% confidence interval of the true mean, if the population standard deviation is 1,151. What is the upper bound of the confidence interval? (round to the correct integer)