Answer:
The margin of error is  [tex]E = 1.96 * \frac{ 0.92}{\sqrt{28 } }[/tex]
Step-by-step explanation:
From the question we are told that
  The sample size is  [tex]n = 28[/tex]
   The  sample  mean is  [tex]\= x = 2.4 \ hr[/tex]
   The  standard deviation is  [tex]\sigma = 0.92 \ hr[/tex]
  Â
Given that the confidence level is 95% the the level of significance can be evaluated 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 value is  [tex]Z_{\frac{\alpha }{2} } = Z_{\frac{0.05}{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{ 0.92}{\sqrt{28 } }[/tex]
     [tex]E = 0.3408[/tex]
