The Student Room Group

S1 - Upper class boundary HELP

Hi,

I have a practice statistics question based on a frequency distribution table, which doesn't show the class limits like usual tables, i.e:

Birth weight (kg)

1.0 -
1.4 -
1.6 -

and so on. Well one of the questions is that what is the upper class boundary of the first class. I thought that with the first class (1.0 - ) it would be
(1.0 - 1.3) if there was a number there as the lower limit, and so the upper class boundary would be 1.35. However, my teacher said that the answer is 1.4 because 1.0 - means it's from 1.0 to 1.4 but doesn't include 1.4. So I was thinking right now, that if this is true and 1.4 isn't included in the first class, then how can it be the upper class boundary of the first class?

Does anyone know how I would calculate the upper and lower class boundaries for such data, as I have never come across this before.

Thanks for your help, it is very much appreciated.
Reply 1
not an expert on this, but for continuous data like weight, the boundaries are the highest and lowest particular values of the range...


we're saying 1.0 =< range < 1.4

so what would you say the max value is? 1.399999...? well, you can keep on adding 9s, and it'll become equivalent to 14 in the end.
Reply 2
Thanks for your help. Do you mean that this only applies for some types of continuous data, such as weight? Or would anything written in this form mean the same thing?
Reply 3
sweet_gurl
Thanks for your help. Do you mean that this only applies for some types of continuous data, such as weight? Or would anything written in this form mean the same thing?

it applies to all continous data. the upper bound of one range is the lower bound of the next.

in contrast, in non-continous data you get gaps, e.g. 1-5, 6-10, 11-15 (dogs/whatever)
Reply 4
sweet_gurl
Thanks for your help. Do you mean that this only applies for some types of continuous data, such as weight? Or would anything written in this form mean the same thing?


sweet_gurl u might find these useful
http://bdaugherty.tripod.com/KeySkills/histograms.html#DISCRETE

http://www.mathsnet.net/asa2/2004/s1.html