safina
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May I ask how come that E[[tex]\bar{X}^{2}[/tex]] = [tex]\frac{\sigma^{2}}{n}[/tex] + [tex]\mu^{2}[/tex]?
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The expected value of the squared sample mean, denoted as E[\bar{X}^{2}], is calculated using the formula E[\bar{X}^{2}] = \frac{\sigma^{2}}{n} + \mu^{2}. This relationship is derived from the properties of random variables, specifically the equation E[Y^2] = Var(Y) + \mu_Y^2. In this context, the mean of the sample mean is represented by μ, while the variance is expressed as σ²/n, where σ² is the population variance and n is the sample size.
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statdad said:Remember that for any random variable [itex]Y[/itex]
[tex] E[Y^2] = Var(Y) + \mu_Y^2[/tex]
What do you know about the mean and variance of the sample mean?