CI for the difference between means (continued) For the estimate of the difference between  1 and  2 we have,  for  =0.05 we have t  /2 =2.228 with 10 d.f è the estimate of the difference is 41.7 è the std error of the difference is 7.24  The confidence interval is then 41.7  2.228*7.24 or 41.7  and the probability statement is  P(25.57   1-  2  57.83) = 0.95 è Note that the interval does not contain the value zero.
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