Find and interpret a 95% confidence interval to estimate the average number of bolts per box for all boxes in the population. Round to 3 decimal places.

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Complete Question

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Answer:

The 95% confidence interval is  [tex]49.85 < \mu < 54.15[/tex]

This means that there is 95% chance that the true population mean is within this interval

Step-by-step explanation:

From the question we are told that

    The  sample size is n = 30  

    The sample mean is  [tex]\= x = 52[/tex]

    The population standard deviation is  [tex]\sigma = 6[/tex]

Given that the confidence level is 95% then the level of confidence is evaluate as

             [tex]\alpha = 100 - 95[/tex]

            [tex]\alpha = 5\%[/tex]

            [tex]\alpha = 0.05[/tex]

Next we obtain the critical value of  [tex]\frac{\alpha }{2}[/tex] from the normal distribution table , the values is

                 [tex]Z_{\frac{\alpha }{2} } = 1.96[/tex]

Generally the margin of error is mathematically represented as

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

substituting values

            [tex]E = 1.96 * \frac{ 6 }{\sqrt{30} }[/tex]

           [tex]E = 2.147[/tex]

The  95% confidence interval is mathematically represented as

          [tex]\= x - E < \mu < \= x + E[/tex]

substituting values

         [tex]52 - 2.147 < \mu < 52 + 2.147[/tex]

         [tex]49.85 < \mu < 54.15[/tex]

       

     

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