78 appears more than any other number, so it is the mode.
83
Range = 89 - 78 = 11
For 98 78 86 88 84 81 93 92 89 and 81: σ=6.2361
400 - 78 - 22 --84 - 16 - 81 - 19 - 27 = 400 - 78 - 22 + 84 - 16 - 81 - 19 - 27 = 241
Median: 80 Mode: 72, 80, 120, 98, 78, 84, 77
70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85 (including 70 and 85)
mean = 81.
902
The composite numbers are: 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86 ,87, 88
62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 87, 88.60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 87, 88, 90
Natural isotopes of krypton are: Kr-78, Kr-80, Kr-81, Kr-82, Kr-83, Kr-84, Kr-86.
82