[填空题]
The following table shows the n8y0ytd ld8un 7umber of overtime hournh8woh652ylqn 40 mlb s worked by employees in a co nw0l 8h6524ybmqonlhmpany.
It is known that the mean number of overtime hours is 1 .
1. Find the value of x .
2. Find the standard deviation of the data. ≈