D -2, 4 is in the second quadrant because the -x brings it to the left side and the positive 4 puts it in the upper of the left side which is the second quadrant
This means that we are 80% confident that the mean of the drive-through service time is between 178.0 seconds and 181.0 seconds. This conclusion was obtained after examined 576 customers. If you want a greater % of confidence you will have to lower the lower bound and increase the upper bound
