Question
Which of the following cannot be valid assignment of probability for elements or outcomes of sample space $s = W_1, W_2,W_{3,} W_4, W_5, W_6, W_7.$
| Elementary events: | $W_1$ | $W_2$ | $W_3$ | $W_4$ | $W_5$ | $W_6$ | $W_7$ |
| $0.7$ | $0.6$ | $0.5$ | $0.4$ | $0.3$ | $0.2$ | $0.1$ |