Question 1124494
since we know the standard deviation of the population and the sample size is > 30, we can use the Normal distribution
:
Standard Error = 10 / square root(50) = 1.4142
: 
z-score = (57.1 - 60) / 1.4142 = -2.05
:
Probability (X < 57.1) associated with a z-score of -2.05 = 0.0202
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