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For the conditions of Exercise 5, how large a random sample must be taken so that\({{\bf{E}}_{\bf{p}}}\left( {{\bf{|}}{{{\bf{\bar X}}}_{\bf{n}}} - {\bf{p}}{{\bf{|}}^{\bf{2}}}} \right) \le {\bf{0}}{\bf{.01}}\)for every possible value ofp (0≤p≤1)?

Short Answer

Expert verified

The needed sample size is \(n \ge 25\)

Step by step solution

01

Given information

Referring to question Exercise 5

02

Finding sample size

Here X is a Bernoulli random variable.

\(So,E\left( {{{\bar X}_n}} \right) = p\)

\(\begin{align}{E_p}\left( {|{{\bar X}_n} - p{|^2}} \right) &= Var\left( {{{\bar X}_n}} \right)\\ &= \frac{{p\left( {1 - p} \right)}}{n}\end{align}\)

This variance will be maximum when p=0.5

\(\begin{align}{E_p}\left( {|{{\bar X}_n} - p{|^2}} \right) &= Var\left( {{{\bar X}_n}} \right)\\ &= \frac{{0.5\left( {1 - 05} \right)}}{n}\\ &= \frac{{0.25}}{n}\end{align}\)

Here given that,

\(\begin{align}{E_p}\left( {|{{\bar X}_n} - p{|^2}} \right) \le 0.01\\\frac{{0.25}}{n} \le 0.01\\n \ge \frac{{0.25}}{{0.01}}\\n \ge 25\end{align}\)

So, the needed sample size is 25

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Most popular questions from this chapter

Question: Consider the calorie count data described in Example7.3.10 on page 400. Now assume that each observation has the normal distribution with unknown mean \({\bf{\mu }}\,\,{\bf{and}}\,\,{\bf{\tau }}\) given the parameter \({\bf{\mu }}\,\,{\bf{and}}\,\,{\bf{\tau }}\). Use the normal-gamma conjugate prior distribution with prior hyper parameters

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Suppose that X1,……,Xn form a random sample from a normal distribution for which the mean is known and the variance is unknown. Construct an efficient estimator that is not identically equal to a constant, and determine the expectation and the variance of this estimator.

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  1. Construct a 2×2 orthogonal matrix for which the first row is as follows: \(\left( {\begin{align}{}{\frac{{\bf{1}}}{{\sqrt {\bf{2}} }}}&{\frac{{\bf{1}}}{{\sqrt {\bf{2}} }}}\end{align}} \right)\)
  2. Construct a 3×3 orthogonal matrix for which the first row is as follows: \(\left( {\begin{align}{}{\frac{{\bf{1}}}{{\sqrt {\bf{3}} }}}&{\frac{{\bf{1}}}{{\sqrt {\bf{3}} }}}&{\frac{{\bf{1}}}{{\sqrt {\bf{3}} }}}\end{align}} \right)\)
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