[填空题]
The following table shows the number j;a:o0titd-*.mvs ;b0jt qpaof ox2gf2t01,v . xoot8 d -o-oyi+ obdihcvertime hours worked by employees in a compfbcdoh8ot+g,ioy2- t2 0odox . -1ivxany.
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. ≈