Let \(Y_i=\alpha ^{i/n}+\epsilon _i\), \(1\le i\le n\). We assume that \(\epsilon _1,\epsilon _2,\ldots ,\epsilon _n\) are independent, identically distributed random variables with \(\E \epsilon _i=0\), \(0<\sigma ^2=\operatorname {Var}\epsilon _i<\infty \) and \(\E \epsilon _i^4<\infty \).
(a) Find the least-squares estimator for \(\alpha \).
(b) Show that the estimator is asymptotically normal.
(c) Find an estimator for \(\sigma ^2\).