a. A score that is 12 points below the mean corresponds to a z-score of z = 21.50. What is the standard deviation? b. A score that is 20 points above the mean corresponds to a z-score of z = 1.25....

a. A score that is 12 points below the mean corresponds to a z-score of z = 21.50. What is the standard deviation?

b. A score that is 20 points above the mean corresponds to a z-score of z = 1.25. What is the standard deviation?