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