[填空题]
The histogram below shows the number of working 4r2n2 jp h i ez0nxpdrr*ak75e4m-w7ihours recorded by vy.qh)t md2mi/fhf g8,ufs6) 145 employees in a f8sy f)quhg t h/vd,im2 .6mf)company during a particular week, each measured correct to the nearest hour and then rounded to the nearest 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.
