Thread: Frequency Distribution (Classes)

1. 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.

2. Originally Posted by Espoir
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

3. help for the problem

Hello Espoir,
I agree with mathaddict.
As you can see in annexe, the classes are represented by intervals.
Bye!

4. 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?

5. Originally Posted by Espoir
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 .

6. 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!