Question 1172473
sample distribution N~(2.4, 0.0432) or mean 2.4 and sd 0.21; the variance is sigma^2/n
probability X^> 2.5 is z > (2.5-2.4)/0.21 or 
z > 0.476
which is probability 0.3170.  This comes from the table or from the calculator 2ndVARS2normalcdf(0.476,6) or any number greater than 6.
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So long as the population itself is normal, the sampling distribution of samples with size 3 will also have a normal distribution with the above parameters.