3.<img src="https://img.yamol.tw/item/1421428-0-5eb9c444be35b.png#s-635,44">

4. ( ) If the mean of a normal distribution is negative, then (A) the standard deviat ion must also be negative (B)'the variance must also be negative (C) a mistake has been made in the computations, because the mean of a normal distribution can not be negative (D) the standard deviation must be zero (E) None of these answers is correct.