Easy. it’s b because when it’s all added up 9 is the answer
So this is asking the cube root of -27 then squared.
Cube root of -27=-3
And -3^2=9
So I believe your answer is 9
<span>a)
Z*_Upper = (76 - 62.7)/2.5 = 5.32
Z*_Lower = (57 - 62.7)/2.5 = -2.28
The requirement is to get p(-2.28 < Z < 5.32) = p(Z<5.32) - p(Z<-2.28).
Use normal distribution table to get the answer for p and multiply with 100 to get the percentage.
The other questions are now easy for you to answer on your own. Hope it helps.
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