The heights of male students entering the University of Hong Kong, X, are normally distributed with a mean of 170.4 cm. It is known that about 2.5% of the students are taller than 190 cm. (a) What is the standard deviation of X? (b) What is the proportion of male students at the University of Hong Kong with a height of 160 cm or less? (c) What is the probability that the mean height of n = 4 randomly selected male students exceeds 175 cm? (d) Male students are randomly selected one after the other. What is the probability that the fif