In Problem 2 as originally worded, "data" don't have standard errors; parameter estimates do.  The intent was that the value 1 is the SD of the 9 differences, not the standard error of their mean.  The original wording was ambiguous.
Problem 3 improve wording for non-English speakers
The BMI comparison problem doesn't provide a place to submit the answer!  (Also,it appears as if the both the diet and placebo INCREASE bmi, but that is another problem.
The BMI comparison problem doesn't provide a place to submit the answer! (Also,it appears as if the both the diet and placebo INCREASE bmi, but that is another problem.
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