Chapter 10: Problem 7
Show that the power function of the sign test is nonincreasing for the hypotheses $$ H_{0}: \theta=\theta_{0} \text { versus } H_{1}: \theta<\theta_{0} $$
/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}
Learning Materials
Features
Discover
Chapter 10: Problem 7
Show that the power function of the sign test is nonincreasing for the hypotheses $$ H_{0}: \theta=\theta_{0} \text { versus } H_{1}: \theta<\theta_{0} $$
All the tools & learning materials you need for study success - in one app.
Get started for free
Let \(x_{1}, x_{2}, \ldots, x_{n}\) be a realization of a random sample. Consider the Hodges-Lehmann estimate of location given in expression (10.9.4). Show that the breakdown point of this estimate is \(0.29\). Hint: Suppose we corrupt \(m\) data points. We need to determine the value of \(m\) which results in corruption of one half of the Walsh averages. Show that the corruption of \(m\) data points leads to $$ p(m)=m+\left(\begin{array}{c} m \\ 2 \end{array}\right)+m(n-m) $$ corrupted Walsh averages. Hence the finite sample breakdown point is the "correct" solution of the quadratic equation \(p(m)=n(n+1) / 4\).
(a) For \(n=3\), expand the mgf (10.3.6) to show that the distribution of the signed-rank Wilcoxon is given by $$ \begin{array}{|l|ccccccc|} \hline j & -6 & -4 & -2 & 0 & 2 & 4 & 6 \\ \hline P(T=j) & \frac{1}{8} & \frac{1}{8} & \frac{1}{8} & \frac{2}{8} & \frac{1}{8} & \frac{1}{8} & \frac{1}{8} \\ \hline \end{array} $$$$ \text { (b) Obtain the distribution of the signed-rank Wilcoxon for } n=4 \text { . } $$
Suppose the random variable \(e\) has \(\operatorname{cdf} F(t) .\) Let \(\varphi(u)=\sqrt{12}[u-(1 / 2)]\), \(0
_{j}\left\\{R\left(Y_{j}\right)>\frac… # Consider the sign scores test procedure discussed in Example \(10.5 .4\). (a) Show that \(W_{S}=2 W_{S}^{*}-n_{2}\), where \(W_{S}^{*}=\\#_{j}\left\\{R\left(Y_{j}\right)>\frac{n+1}{2}\right\\} .\) Hence \(W_{S}^{*}\) is an equivalent test statistic. Find the null mean and variance of \(W_{S}\). (b) Show that \(W_{S}^{*}=\\#_{j}\left\\{Y_{j}>\theta^{*}\right\\}\), where \(\theta^{*}\) is the combined sample median. (c) Suppose \(n\) is even. Letting \(W_{X S}^{*}=\\#_{i}\left\\{X_{i}>\theta^{*}\right\\}\), show that we can table \(W_{S}^{*}\) in the following \(2 \times 2\) contingency table with all margins fixed: $$ \begin{array}{|c|c|c|c|} \hline & Y & X & \\ \hline \text { No. items }>\theta^{*} & W_{S}^{*} & W_{X S}^{*} & \frac{n}{2} \\\ \hline \text { No. items }<\theta^{*} & n_{2}-W_{S}^{*} & n_{1}-W_{X S}^{*} & \frac{n}{2} \\ \hline & n_{2} & n_{1} & n \\ \hline \end{array} $$ Show that the usual \(\chi^{2}\) goodness-of-fit is the same as \(Z_{S}^{2}\), where \(Z_{S}\) is the standardized \(z\) -test based on \(W_{S}\). This is often called Mood's median test; see Example \(10.5 .4 .\)
Let \(\widehat{F}_{n}(x)\) denote the empirical cdf of the sample \(X_{1}, X_{2}, \ldots, X_{n} .\) The distribution of \(\widehat{F}_{n}(x)\) puts mass \(1 / n\) at each sample item \(X_{i} .\) Show that its mean is \(\bar{X}\). If \(T(F)=F^{-1}(1 / 2)\) is the median, show that \(T\left(\widehat{F}_{n}\right)=Q_{2}\), the sample median.
What do you think about this solution?
We value your feedback to improve our textbook solutions.