Results 1 to 6 of 6

Math Help - Frequency Distribution (Classes)

  1. #1
    Newbie
    Joined
    Dec 2009
    Posts
    3

    Unhappy Frequency Distribution (Classes)

    Hello there,

    Firstly, I'm not sure if this should be in Advanced or Basic, but I put it in basic because I don't think the question I'm asking is advanced.

    I've been given a task and one of the question asks me to put the data into a Frequency Distribution table.

    Basically, I can't get my head around what the classes should be.

    There are 100 figures, going from 0-17. So the range is 17.
    I am told that I need to group this data into 9 equal classes, with midpoints 1, 3, 5 etc. This is just causing me a problem now, I can't figure out what the classes should be.

    I tried:

    0 - 2
    3 - 4
    5 - 6...

    Until I realised the midpoints were not 1, 3, 5.

    So now my latest assumption is that the classes are:

    0 - 1.99
    2 - 3.99
    4 - 5.99...

    This also finishes into 9 equal classes (16 - 17.99) however, if we add both of them up and divide them by 2 to get the midpoint, we realise the midpoint is 0.995.

    Could somebody please help me out? I must be missing something, I just don't understand how to go about it. I've tried several times, but this 1, 3, 5 midpoint is just blocking me now.

    Thank you in advance.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by Espoir View Post
    Hello there,

    Firstly, I'm not sure if this should be in Advanced or Basic, but I put it in basic because I don't think the question I'm asking is advanced.

    I've been given a task and one of the question asks me to put the data into a Frequency Distribution table.

    Basically, I can't get my head around what the classes should be.

    There are 100 figures, going from 0-17. So the range is 17.
    I am told that I need to group this data into 9 equal classes, with midpoints 1, 3, 5 etc. This is just causing me a problem now, I can't figure out what the classes should be.

    I tried:

    0 - 2
    3 - 4
    5 - 6...

    Until I realised the midpoints were not 1, 3, 5.

    So now my latest assumption is that the classes are:

    0 - 1.99
    2 - 3.99
    4 - 5.99...

    This also finishes into 9 equal classes (16 - 17.99) however, if we add both of them up and divide them by 2 to get the midpoint, we realise the midpoint is 0.995.

    Could somebody please help me out? I must be missing something, I just don't understand how to go about it. I've tried several times, but this 1, 3, 5 midpoint is just blocking me now.

    Thank you in advance.
    HI

    The classes would be

    0-2
    2-4
    4-6
    6-8
    8-10
    10-12
    12-14
    16-18

    Now their midpoint matches . Take the first class for example , the data in this class can be anything from 0 to before 2 , 2nd class : data from 2 anything before 4 .

    The other way of writing this would be

    <2
    <4
    <6
    <8
    <10
    <12
    <14
    <16
    <18
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Dec 2009
    From
    São Tomé
    Posts
    12

    help for the problem

    Hello Espoir,
    I agree with mathaddict.
    As you can see in annexe, the classes are represented by intervals.
    Bye!
    Attached Thumbnails Attached Thumbnails Frequency Distribution (Classes)-classes.jpg  
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Dec 2009
    Posts
    3
    Hello guys!

    Thank you for the swift replies, sorry about my late one, I was working on my other questions yesterday until I knew what to do with these classes!

    Yes that sounds like the correct one, and I had also thought about it. However I thought that this was wrong? Because doesn't this mean that the classes "overlap"? Or is that due to something else?

    Because I've read that a frequency cannot be in more than one class, which is understandable. So basically, it wouldn't be clear to the reader (examiner) if I had included a 2 in the 0-2 or in 2-4. Unless I state this somewhere or go with the >2 option?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by Espoir View Post
    Hello guys!

    Thank you for the swift replies, sorry about my late one, I was working on my other questions yesterday until I knew what to do with these classes!

    Yes that sounds like the correct one, and I had also thought about it. However I thought that this was wrong? Because doesn't this mean that the classes "overlap"? Or is that due to something else?

    Because I've read that a frequency cannot be in more than one class, which is understandable. So basically, it wouldn't be clear to the reader (examiner) if I had included a 2 in the 0-2 or in 2-4. Unless I state this somewhere or go with the >2 option?
    when you write it like that , its understood .

    0-2 here means 0 to anything before 2 where 2 does not belong to this class . The other way to write this is <2 and so on , to avoid potential confision .
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Dec 2009
    Posts
    3
    Hmm okay well thank you for that.

    I think I am going to state in a little sentence above or below the table just to make sure it's clear how the data is laid out.

    Okay, thanks for the help, it's appreciated!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Help with Frequency Distribution?
    Posted in the Statistics Forum
    Replies: 1
    Last Post: March 24th 2011, 02:12 PM
  2. frequency distribution
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: May 19th 2010, 07:03 AM
  3. Frequency Distribution?
    Posted in the Business Math Forum
    Replies: 3
    Last Post: April 22nd 2009, 11:41 AM
  4. Replies: 3
    Last Post: January 22nd 2009, 05:55 PM
  5. frequency distribution .........
    Posted in the Statistics Forum
    Replies: 2
    Last Post: March 23rd 2007, 03:16 AM

Search Tags


/mathhelpforum @mathhelpforum