Consider the table below of average wing length minus tail length for ni = 24 birds in each of 10 species of flycatcher. Species 1 2 3 4 5 6 7 8 9 10 Average wing-tail (n = 24) 13.6 15.4 14.7 12.4 9.2 13.7 10.3 7.0 9.5 9.5

[3 points] What is the grand mean for this collection of observations?

[4 points] If it is assumed that the 10 populations all have the same population mean and same population variance 2, how variable should these 10 sample means be, in terms of 2 (that is, if X _i is the sample mean for the ith species, what is Var(X _i) )?