Need help understanding questions 1-7 about finding z scores from percentiles.

Directions: For the problems below all of the populations are normally distributed. Draw the normal curve and shade the appropriate are for the given Probability or area and find the z-score. 1. Mean = 2 o = 1 find the z-score associated with a probability of .5 2. Mean = 3 o = -1.2 find the z-score associated with an area of .5 3. Mean = 1 o = .2 find the z-scores centered about the mean containing 50 percent of the data 4. Mean = 80 a = 10 find the z-score associated with a probability of .25 5. Mean = 80 a = 10 find the z-score associated with an area of .75 6. Mean = 65 0 = 15 find the z-score associated with a percentile rank of .70 7. Mean = 1 o = .0001 find the z-score associated with a probability of .35