1.(2+3 * 2+6 * 4+10 * 2+10)/10 = 6.2 Note that the average value of the first question is not accurate, because people who exceed10 hours do not know the specific time; 2. Median: Sort this set of data from small to large: 2336661010.

Average value of the middle two numbers: 6.3.A+B+C+D = 84 * 4 = 3 16 (4), A+B = 72 * 2 = 144 (1), and B+C = 76 * 2 = 66. B+D= 160(3), while (1)+(2)-(3) gives a+b+c-d =144+152-160 =. 2d = 316-136 =180 is obtained from (4)-(5).

So D= 180/2=90.