I think I figured it out.

If the margin of error is 5 with a margin of error of 2, then, the number of marbles can be

Code:

93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 // error of 7
94 95 96 97 98 99 100 101 102 103 104 105 106 // error of 6
95 96 97 98 99 100 101 102 103 104 105 // error of 5
96 97 98 99 100 101 102 103 104 // error of 4
97 98 99 100 101 102 103 // error of 3

Does anyone see where to go from here, how do I express the margin of error as a single number? Seems like you can have a margin of error but some parts of it are more likely of appearing.

So there's 55 numbers.

93: 1/55

94: 2/55

95: 3/55

96: 4/55

97: 5/55

98: 5/55

99: 5/55

100: 5/55

101: 5/55

102: 5/55

103: 5/55

104: 4/55

105: 3/55

106: 2/55

107: 1/55