[Math] Class Limits, boundaries, midpoint, relative frequency

statistics

I have a list:

85
45
75
60
90
90
115
30
55
58
78
120
80
65
65
140
65
50
30
125
75
137
80
120
15
45
70
65
50
45
95
70
70
28
40
125
105
75
80
70
90
68
73
75
55
70
95
65
200
75
15
90
46
33
100
65
60
55
85
50
10
68
99
145
45
75
45
95
85
65
65
52
82

Sorry for the poor formatting, but I created a program that would count the frequencies, etc. and I still am getting the problem wrong.

The class limits make sense to me since the smallest value is 10 and you just need to add 28 (the class width), and the next should be 48, right? Or am I completely off base?

Class boundaries will make sense once I get the right values for the class limits.

The midpoint should be the lower limit + the upper, so wouldn't the midpoint of (10 + 38)/2 be 24??

And relative frequency is just the frequency divided by the total frequencies, right?

image

Thanks for your help :/

Best Answer

Here's the tally of your numbers:

{{65, 8}, {75, 6}, {45, 5}, {70, 5}, {90, 4}, {50, 3}, {55, 3}, {80, 
  3}, {85, 3}, {95, 3}, {15, 2}, {30, 2}, {60, 2}, {68, 2}, {120, 
  2}, {125, 2}, {10, 1}, {28, 1}, {33, 1}, {40, 1}, {46, 1}, {52, 
  1}, {58, 1}, {73, 1}, {78, 1}, {82, 1}, {99, 1}, {100, 1}, {105, 
  1}, {115, 1}, {137, 1}, {140, 1}, {145, 1}, {200, 1}}

And here's the histogram with bin width = 1, thus replicating the above tally:

enter image description here

The mean is 73.7, the quartiles are {54.3, 70, 90}. There's many more summary statistics that can computed.

What method are you using to classify (ie, partition the x-axis) or cluster the data?

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