posted by John .
find z such that 5.2% of the standard normal curve lies to the left of z
Use that table again.
You have to do a reverse lookup on a standard distribution table to find the answers.
Or, if you have excel, use the NORMSINV function.
1. P(X≤z) = 0.052
z = -1.626
in Excel, the cell for your result has the formula =NORMSINV(0.052). easy. Or you can find your favorite z-table and find out. If your z-value table only has the values for z≥0, just find the value of z for P(X≤z) = 0.948, and you'll have -z.