4.26 The manager at a firm in Tokyo wants to organize a trip for his team in the summer of 2020, but some employees have already applied for leave. To be better prepared, he estimates the probabilities of the employees who are taking day(s) off during the summer season in the following table.

Number of days off 0 1 2 3 4 5 Probability 0.05 0.30 0.45 0.10 0.07 0.03 Find the mean and the standard deviation of the number of days off.