Chapter 4: Problem 3
Define the sets \(A_{1}=\\{x:-\infty
Chapter 4: Problem 3
Define the sets \(A_{1}=\\{x:-\infty
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Get started for freeLet \(X_{1}, X_{2}, \ldots, X_{n}\) be a random sample from a continuous-type
distribution.
(a) Find \(P\left(X_{1} \leq X_{2}\right), P\left(X_{1} \leq X_{2}, X_{1} \leq
X_{3}\right), \ldots, P\left(X_{1} \leq X_{i}, i=2,3, \ldots, n\right)\)
(b) Suppose the sampling continues until \(X_{1}\) is no longer the smallest
observation (i.e., \(X_{j}
Let \(Y_{1}
This data set was downloaded from the site http://lib.stat.cmu.edu/DASL/ at Carnegie-Melon university. The original source is Willerman et al. (1991). The data consist of a sample of brain information recorded on 40 college students. The variables include gender, height, weight, three IQ measurements, and Magnetic Resonance Imaging (MRI) counts, as a determination of brain size. The data are in the rda file braindata. rda at the sites referenced in the Preface. For this exercise, consider the MRI counts. (a) Load the rda file braindata.rda and print the MRI data, using the code: \(\mathrm{mri}<-\) braindata \([, 7] ;\) print(mri). (b) Obtain a histogram of the data, hist \((m r i, p r=T)\). Comment on the shape. (c) Overlay the default density estimator, lines (density(mri)). Comment on the shape. 4.1.10. This data set was downloaded from the site http://lib.stat.cmu.edu/DASL/ at Carnegie-Melon university. The original source is Willerman et al. (1991). The data consist of a sample of brain information recorded on 40 college students. The variables include gender, height, weight, three IQ measurements, and Magnetic Resonance Imaging (MRI) counts, as a determination of brain size. The data are in the rda file braindata. rda at the sites referenced in the Preface. For this exercise, consider the MRI counts. (a) Load the rda file braindata.rda and print the MRI data, using the code: \(\mathrm{mri}<-\) braindata \([, 7] ;\) print(mri). (b) Obtain a histogram of the data, hist \((m r i, p r=T)\). Comment on the shape. (c) Overlay the default density estimator, lines (density(mri)). Comment on the shape.
Let \(Y_{1}
Let \(x_{1}, x_{2}, \ldots, x_{n}\) be the values of a random sample. A bootstrap sample, \(\mathbf{x}^{* \prime}=\left(x_{1}^{*}, x_{2}^{*}, \ldots, x_{n}^{*}\right)\), is a random sample of \(x_{1}, x_{2}, \ldots, x_{n}\) drawn with replacement. (a) Show that \(x_{1}^{*}, x_{2}^{*}, \ldots, x_{n}^{*}\) are iid with common cdf \(\widehat{F}_{n}\), the empirical cdf of \(x_{1}, x_{2}, \ldots, x_{n}\) (b) Show that \(E\left(x_{i}^{*}\right)=\bar{x}\) (c) If \(n\) is odd, show that median \(\left\\{x_{i}^{*}\right\\}=x_{((n+1) / 2)}\). (d) Show that \(V\left(x_{i}^{*}\right)=n^{-1} \sum_{i=1}^{n}\left(x_{i}-\bar{x}\right)^{2}\).
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