Question

With a known population mean of 100, and a known standard error of the mean of 7.5, what is the probability of selecting at random a sample whose mean is 110 or greater?


I need help getting this started, thanks

Answer 1

Finding z-score with your data:

z = (110 - 100)/(7.5)

Finish the calculation. Check a z-table for your probability using the z-score (remember the question is asking "whose mean is 110 or greater" when looking at the table).