The confidence interval is expressed as a percentage the most frequently quoted percentages are 90 95 and 99. A confidence interval for a difference between means is a range of values that is likely to contain the true difference between two population means with a certain level of confidence. To find the MSE subtract your sample mean from each value in the dataset square the resulting number and divide that number by n 1 sample size minus 1.
In the following lesson we will look at how to use the formula for each of these types of intervals.
Expect that to happen 5 of the time for a 95 confidence interval. In other words we subtracting the before and after values to find the difference. The first column df stands for degrees of freedom and for confidence intervals on the mean df is equal to N - 1 where N is the sample size. Using this sample youve estimated the sample mean to be 75.