Exercise

Evaluating the effectiveness of stem cell treatment

Now that we set out hypotheses, we can calculate the observed difference in means between the treatment and control groups. The stem.cell data frame gives us the pumping capacity of the heart before and after the experiment. So first we need to find the difference between these for each experimental unit, and then use these change values to calculate the observed difference in mean change between treatment and control groups.

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Add a column to stem.cell named change, equal to after minus before.