A decision maker is interested in estimating the mean of a population based on a random sample. She wants the confidence level to be ​% and the margin of error to be . She does not know what the population standard deviation​ is, so she has selected the pilot sample below. Based on this pilot​ sample, how many more items must be sampled so that the decision maker can make the desired confidence interval​ estimate? The decision maker should sample nothing more items to make the desired confidence interval estimate.

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Complete Question

The complete question is shown on the first uploaded image

Answer:

The value is [tex]n = 146093[/tex]

Step-by-step explanation:

From the question we are told that

    The margin of error is  [tex]E = 0.04[/tex]

   The data is  

      8.70      4.79    10.95   15.19    14.06

      16.99     1.22    9.02    14.39     5.73

      7.28     3.22     2.66    6.13       6.93

Generally the sample mean is mathematically represented as

    [tex]\= x = \frac{\sum x_i}{n}[/tex]

=>  [tex]\= x = \frac{ 8.70 + 4.79 +\cdots + 6.93}{15}[/tex]

=>  [tex]\= x = 8.48[/tex]

Generally the standard deviation is mathematically represented as  

       [tex]\sigma = \sqrt{ \frac{ \sum (x_i - \= x)}{n} }[/tex]

=>     [tex]\sigma = \sqrt{ \frac{ (8.70 - 8.48 )^2 + ( 8.70 - 8.48)^2 + \cdots + (6.93 - 8.48)^2 }{15} }[/tex]

=>     [tex]\sigma = 5.14[/tex]

From the question we are told the confidence level is  98% , hence the level of significance is    

      [tex]\alpha = (100 - 98 ) \%[/tex]

=>   [tex]\alpha = 0.02[/tex]

Generally the degree of freedom is mathematically represented as

      [tex]df = n -1[/tex]

=>   [tex]df = 15 -1[/tex]  

=>   [tex]df = 14[/tex]  

Generally from the t distribution table the critical value  of   at a degree of freedom of   is  

   [tex]t_{\frac{\alpha }{2} ,  14 } = 2.9768 [/tex]

Generally the sample size is mathematically represented as

      [tex]n =[ \frac{t_{\frac{\alpha }{2} , 14 } * \sigma }{E} ]^2[/tex]

=>    [tex]n =[ \frac{ 2.9768 * 5.136 }{0.04} ]^2[/tex]

=>    [tex]n = 146093[/tex]

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