Standardizing the possible values in the previous exercise means that we transform the possible values (0 and 1) by subtracting the population mean and dividing by the population standard deviation. Here this yields (1 − 0.3)/

√

0.21 = 0.7/

√

0.21 and (0−0.3)/

√

0.21 = −0.3/

√

0.21, respectively. The probabilities associated with these two values are 0.7 and 0.3. Verify that the expected value of the standardized values is 0 and the variance is 1.