Answer:
18: mean = 70.5
median = 76.5
range = 76
20:
mean = 70.83
median = 76.5
range = 76
84:
mean = 81.5
median = 79.5
range = 20
78:
mean = 80.5
median = 81
range = 20
81:
mean = 81
median = 80.25
range = 20
82.5:
mean = 81.5
median = 80.25
range = 20
Explanation:
mean = average = sum of numbers / amount of numbers present
median = middle number (arranged least to greatest)
range = largest number - smallest number