In a standard normal distribution:

Approximately what proportion of the observations are between 1.8 and 2.8 standard deviations greater than the mean or between 1.8 and 2.8 standard deviations less than the mean? (3 decimal places)
b) Suppose we want to find a value from a normal distribution with a probability of 0.15 to the right. What would be the z-score for that value?