[填空题]
The histogram below shows thlul.a;j+ o( im(*.4fa ztfiv2x kg( cce number of wo.klztbz(: ab9 3spk-lvsy0w )rking hours recorded by 145 employees in a company during a particular week, each measured correct to the nearest hour and then rounded to the nearess9l3y(:0a.-l )vsw b tpkzbzkt units of 10 hours.
1. Write down the modal working time of the employees. hours
2 . Find the median working time.
The upper quartile is 50 working hours. hours
3. Calculate
(1) the lower quartile; hours
(2) the interquartile range.
