Chapter 2.11

Testing Linear Hypotheses in the Gaussian Regression Model

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Problem 2.11.1

Construct an FF-test of significance level α\alpha for testing the hypothesis H0:β2=β1H_{0}: \beta_{2}=\beta_{1} in problem 2 from the self-study problems of section 9.

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Problem 2.11.2

X1,…,XnX_{1}, \ldots , X_{n} is a sample from the distribution N(a1,σ2)\mathscr {N}\left(a_{1}, \sigma^{2}\right), Y1,…,YmY_{1}, \ldots , Y_{m} is a sample from the distribution N(a2,σ2)\mathscr {N}\left(a_{2}, \sigma^{2}\right), Z1,…,ZkZ_{1}, \ldots , Z_{k} is a sample from the distribution N(a3,σ2)\mathscr {N}\left(a_{3}, \sigma^{2}\right). Construct an FF-test of size α\alpha for testing the hypothesis:

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(a)

H0:a1=a2H_{0}: a_{1}=a_{2} and a1+a2=a3a_{1}+a_{2}=a_{3};

(b)

H0:a1=2a2H_{0}: a_{1}=2 a_{2} and a1+3a2=a3a_{1}+3 a_{2}=a_{3}.

Problem 2.11.3

Solve problem 11.211.2 using theorem 11.111.1.

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Problem 2.11.4

Let Xi∼N(a,iσ2),i=0,1,…,n,Yi∼N(jb,σ2),j=1,…,mX_{i} \sim N\left(a, i \sigma^{2}\right), i=0,1, \ldots , n, Y_{i} \sim \mathscr {N}\left(jb, \sigma^{2}\right), j=1, \ldots , m be independent random variables, where a,b,σ2a, b, \sigma^{2} are unknown parameters. Reduce the problem to a linear model and construct an FF-test of size α\alpha for testing the hypothesis H0:a+b=1H_{0}: a+b=1.

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Problem 2.11.5

Using the linear regression method, construct an approximation of the function f(x)f(x) by a cubic polynomial based on the following data:

f(xi)f\left(x_{i}\right)3.93.95.05.05.75.76.56.57.17.17.67.67.87.88.18.18.48.4
xix_{i}4.04.05.25.26.16.17.07.07.97.98.68.68.98.99.59.59.99.9
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Problem 2.11.6

Let Xij∼N(μj,σ2),i=1,…,nj,j=1,…,kX_{i j} \sim \mathscr {N}\left(\mu_{j}, \sigma^{2}\right), i=1, \ldots , n_{j}, j=1, \ldots , k, be independent random variables, and let {μj}j=1k,σ2\left\{ \mu_{j}\right\}_{j=1}^{k}, \sigma^{2} be unknown parameters. Denote N=∑j=1knjN=\sum_{j=1}^{k} n_{j}. To test the homogeneity hypothesis H0:μ1=…=μkH_{0}: \mu_{1}=\ldots =\mu_{k} we use the FF-test of one-way analysis of variance with the following statistic

R=1k−1∑j=1knj(X.j−X..)21N−k∑j=1k∑i=1nj(Xij−X.j)2, R=\frac{\frac{1}{k-1} \sum _{j=1}^{k} n_{j}\left(X_{. j}-X_{. .}\right)^{2}}{\frac{1}{N-k} \sum _{j=1}^{k} \sum _{i=1}^{n_{j}}\left(X_{i j}-X_{. j}\right)^{2}},

where

X.j=1nj∑i=1njXij,X..=1k∑j=1kX.j X_{. j}=\frac{1}{n_{j}} \sum _{i=1}^{n_{j}} X_{i j}, X_{. .}=\frac{1}{k} \sum _{j=1}^{k} X_{. j}

Prove that when H0H_{0} holds, R∼Fk−1,N−kR \sim F_{k-1, N-k}.

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