Question

The probabilities that a surgeon operates on 3, 4, 5, 6 or 7 patients in any day are 0.15, 0.10, 0.20, 0.25 and 0.30, respectively. Find the average number of patients that a surgeon operates on a day.

Answer 1

$EX=3\cdot 0.15+4\cdot 0.1+5\cdot 0.2+6\cdot 0.25+7\cdot 0.3=5.45$