This is personal study note Copyright and original reference: https://www.youtube.com/watch?v=lQx0mYMQ5C8&list=PLsri7w6p16vvQCo9pmuRNY_SYoOGB6bWM&index=2&t=0s ================================================================================ ================================================================================ Paired sample ================================================================================ Example table $$$X_1$$$: mean weight (before) $$$X_2$$$: mean weight (after) ================================================================================ $$$\bar{d}_x$$$: mean difference $$$s^2_{d_x}$$$: variance of difference (wrt weight X) $$$s_{d_x}$$$: standard deviation of difference (wrt weight X) $$$s_{\bar{d}_x}$$$: standard ================================================================================ ================================================================================ ================================================================================ ================================================================================ ================================================================================ ================================================================================ Confidence interval ================================================================================