[9] X is a Gaussian random variable with variance 0.25. The mean of X is estimated by taking the sample mean of independent samples of X. If the mean needs to be estimated within 0.01 from the actual mean with a confidence coefficient of 0.99, find the minimum number of samples needed in the estimation.

Respuesta :

Answer:

The minimum number of samples required is  [tex]n = 16641 [/tex]  

Step-by-step explanation:

From the question we are told that

    The variance is  [tex]\sigma^2 = 0.25[/tex]

    The margin of error is [tex]E = 0.01[/tex]

From the question we are told the confidence coefficient is  0.99 , hence the level of significance is    

      [tex]\alpha = (1 - 0.99 ) \%[/tex]

=>   [tex]\alpha = 0.01[/tex]

Generally from the normal distribution table the critical value  of  [tex]\frac{\alpha }{2}[/tex] is  

   [tex]Z_{\frac{\alpha }{2} } =  2.58[/tex]

Generally the standard deviation is

      [tex]\sigma =\sqrt{\sigma^2}[/tex]

=>   [tex]\sigma =\sqrt{0.25}[/tex]

=>   [tex]\sigma =0.5[/tex]

Generally the sample size is mathematically represented as  

    [tex]n = [\frac{Z_{\frac{\alpha }{2} } *  \sigma }{E} ] ^2[/tex]

=>      [tex]n = [\frac{2.58 } *  0.5 }{0.01 } ] ^2[/tex]

=>      [tex]n = 16641 [/tex]