Question 1103809
This is presumably normally distributed.
z=(x-mean)/sd=(842-848)/15=-6/15=-0.4
z=(863-848)/15=+1
probability of z between those two numbers is 0.4968
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The next part is normally distributed (at least no reason given to suggest it isn't).
Mean is 848
The z values have the sd modified to be s/(sqrt(27)=2.89
Therefore, the z values will be between -6/2.89=-2.08 and 15/2.89=5.19
That probability is now 0.9812.