The Normal distribution with mean

= 6.8 and standard deviation

= 1.6 is a good description of the Iowa Test vocabulary scores of seventh grade students in Gary, Indiana. This is a continuous probability model for the score of a randomly chosen student. Figure 3.1 (p. 68) pictures the density curve. Call the score of a randomly chosen student X for short.

Note:If necessary, use < = to representand > = to represent.

(a) Write the event "the student chosen has a score of 5.2 or lower" in terms of X.

(b) Find the probability of an event which represents "the student chosen has a score of 5.2 or lower".