3. The variable \(X\) represents the marks out of 150 scored by a group of students in an examination. The following ten values of \(X\) were obtained:
$$60,66,76,80,94,106,110,116,124,140 .$$
- Write down the median, \(M\), of the ten marks.
- Using the coding \(y = \frac { x - M } { 2 }\), and showing all your working clearly, find the mean and the standard deviation of the marks.
- Find \(\mathrm { E } ( 3 X - 5 )\).