margin of error = 0.025; confidence level = 95%; likely range=0.3 to 0.4 The required sample size is n =. Round up to the nearest whole number.)

Find the critical value tc for a 95% confidence level when the sample size is 13.   A. 1.753   B. 2.179   C. 2.160   D. 1.96

Allen's hummingbird (Selasphorus sasin) has been studied by zoologist Bill Alther.t Suppose a small group of 14 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 o = 0.22 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

A survey of 1000 people was conducted. 44% said they found it hard to adopt a child in the US. margin of sampling is + or - 3%. with a 95% confidence level. Use the margin of error for a confidence interval estimate. Whart population parameter are we estimating for this sample statistic