The probability of the treatment group mean being lower than control groups mean by 15 points or more will be 0.027.
<h3>How to calculate the probability?</h3>
Based on the information given, let the assumption that the frequency for the points greater than 15 include 20, 4, and 3 while the entire population is 1000.
Then, the probability of the treatment group mean being lower than control groups mean by 15 points or more will be:
= (20 + 4 + 3)/1000
= 27/1000
= 0.027
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