1. True or False. Justify for full credit.
(a) If A and B are any two events, then P(A AND B) = P(A) + P(B).
(b) If the variance of a data set is 0, then all the observations in this data set must be identical.
(c) A normal distribution curve is always symmetric to its mean.
(d) When plotted on the same graph, a distribution with a mean of 60 and a standard deviation of 5 will look more spread out than a distribution with a mean of 40 and standard deviation of 8. 更多
