Question 1071056
z=(x-mean)/sigma/sqrt(n)
> (52-50.4)/11.8/sqrt(42)=1.6/1.82=0.1898
probability is 0.1898
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< (47.5-50.4)/11.8/sqrt(42)=less than -2.9/1.821 or < z of -1.592
Probability is 0.0557
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<-10.4/1.821 or z< -5.711
This is <<0.0001
If that is the case, then the claim is not likely to be true.