The boundaries are found using these formulas:
B_U=L_U+1/2(M) and
B_L=L_L-1/2(M),
where B_U is the upper boundary, B_L is the lower boundary, L_U is the upper limit of the data, L_L is the lower limit of the data, and M is the unit of measurement.
Firstly we find the unit of measurement. From 125-131 we seem to be counting in ones, thus our unit of measurement is M=1. Next we find L_U and L_L. These are simply the highest and lowest numbers, so we get L_U=131 and L_L=125. We now plug these numbers into the equation to get:
B_U=131+1/2(1)" "B_L=125-1/2(1)
B_U=131+1/2" "B_L=125-1/2
B_U=131.5" "B_L=124.5
Therefore the boundaries of 125-131 are 124.5 and 131.5.
I invite you too lok at Gamaliel B's answer for more details.
The width (or range) is found by subtracting the highest value from the lowest value, which looks like this:
131-125=6, therefore 6 is the width (or range).
The midpoint p is found like this:
p=(L_L+L_U)/2
where p is the midpoint, and L_L & L_U are the lower and upper limits of the data, respectively. (The midpoint is just the average of the lowest and highest values.) We know that L_L=125 and L_U=131. Plug these into the formula to get
p=(125+131)/2
p=256/2
p=128, the midpoint.
I hope I helped!
