Question: The mean wage rate for all the workers in a factory is 24.85 per hour. The wage rate for these workers is normally distributed with the population standard deviations of $6.52. If you selected a sample of 40 workers from this factory, then what is the probability that the sample mean is more than $25.00 per hour?  Edit

Answer: Mean mu=24.85
Standard deviation s=6.52
X=25
So, P(X>25)
=P(Z>(25 - 24.85) / 6.52)
=P(Z>0.023006)
=0.49082
  Edit