In: Statistics and Probability
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)
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