Question: how to calculate confidence interval median?
Answer: For example: ... 
The median difference is halfway between the 6th and 7th largest values i.e., between -0.9 and -0.7 = -0.8. ... 
So an approximate 95% confidence interval is given by the 3rd and 10th ranked values (-3.2, -0.2), compared to a 95% confidence interval for the mean which would be (-2.49, -0.57).