please solve the problem "by hand" and R

show detailed works and steps, use R and show the commands.

please don't just give me an R output Please provide detailed steps how you get the answers.

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Participants in an exercise program had the following weights before and after the program. Participant Weight Before Weight After 1 18 22 21 25 16 17 22 24 19 16 24 29 17 20 21 23 23 19 14 15 11 16 15 12 16 18 13 19 26 14 18 18 15 20 24 16 12 18 17 22 25 18 15 19 19 17 16 20 18 20 Use a 0.05 level of significance to test the null hypothesis #1 - #2 = 0 against the alternative hypothesis #1 - /2 > 0, and thus judge whether the exercises are effective. State the assumptions you made