statistics
posted by patina on .
An average office worker uses 10000 sheets of paper each year. Assume that the population standard deviation is 3000 sheets per year.
Is it unusual for the office worker to use over 15000 sheets each year?
What % of workers use at least 8000 sheets per year?
Find P30. Interpret.
In a random sample of 100 office workers, find the probability that the mean number of sheets of paper used per year does not exceed 10500.

Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score. For percent, multiply by 100.
What do you mean by "P30"?
Since the last question involves a distribution of means, use:
Z = (scoremean)/SEm
SEm = SD/√n
Use the same table.