Answer:
D. A value of 0.9 is more than 2 standard deviations from the mean.
Step-by-step explanation:
A is wrong, because the standard deviation is +/-0.15 (the measure up or down from the mean)
B is wrong, because the mean is exactly 0.5
C is wrong, because 1 standard deviation up from the mean is 0.65, and 0.7 is outside of that.
