Given that z^20 = -2 and z^50 = -1, which of the following do you know?
•The variance is 10.
•The standard deviation is 30.
•The mean is 80.
•The median is 40.
•The data point x = 20 is 2 standard deviations from the mean.
•The data point x = 50 is 1 standard deviation from the mean.
•The data point x = 45 has a z-value of 1.5.