A random sample of 134 students has a test score average of 78 with a standard...

A random sample of 134 students has a test score average of 78 with a standard deviation of 10.4. Find the margin of error if the confidence level is 0.99. (Round answer to two decimal places)

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Expert Solution

Level of Significance ,    α =    0.01
degree of freedom=   DF=n-1=   133
't value='   tα/2=   2.61   [Excel formula =t.inv(α/2,df) ]

Standard Error , SE = s/√n =   10.40/ √   134   =   0.8984
margin of error , E=t*SE =   2.6133   *   0.8984   =   2.35

orchestra answered 1 year ago

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