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 (d) Find the sample size necessary for an 80% confidence level with a maximal margin of error E = 0.06 for the mean weights of the hummingbirds. (Round up to the nearest whole number.) hummingbirds

A survey of credit card holders revealed that Americans carried an average credit card balance of $3900 in 1995 and $3300 in 1994 (U.S. News & World Report, January 1, 1996). Suppose that these averages are based on random samples of 400 credit card holders in 1995 and 450 credit card holders in 1994 and that the population standard deviations of the balances were $880 in 1995 and $810 in 1994. Construct a 95% confidence interval for the difference between the mean credit card balances for all credit card holders in 1995 and 1994. a. ($285.81, $414.19) b. ($435.81, $700.19) c. ($845.81, $9984.19) d. ($485.81, $714.19)

suppose a 95% confidence interval for a correlation is 0.32 to 0.48. Give a value for the population correlation p that would be plausible and a value that would be implausible

The results below are based on data collected on campus as part of a student project for an introductory statistics class at UF. If there is more than one group/treatment, the first group mentioned is group 1.  Data was collected to compare the proportion of "Greeks" and non-"Greeks" who voted for Obama in 2012. "Greeks" are students who belong to a fraternity or sorority. The p-value was 0.00, and the 95% confidence interval was ( -0.534,  -0.202). This problem is about   _ two independent proportions ? _ The sign of the alternative hypothesis should be      _ not = ? _ Based on the p-value we can       _ reject the Ho _  at alpha = 0.05. At which alpha levels could we Reject Ho?       _ all of usual alpha levels _ Are the results statistically significant at alpha=0.01?      _ yes _ We have    _ very strong evidence _  to say that the proportion of "Greeks" who voted for Obama is different from the proportion of non-"Greeks". We are 95% confident that the proportion of "Greeks" who…