Please help me draw a histogram

hi!
I haven t done these in a while & don t have the answers to these questions,they re biology qs, I have to draw a histogram,can t remember how to get the frequency & how to organise this :colondollar:

Rep for your help & also for answers that back up other ppl s answers/corrections.
Thanks :biggrin:

(edited 13 years ago)

histogram question.jpg51.4KB

Reply 1

hissyfit

OP

15

PLEASE somebody?
It can t be that impossible

Reply 2

BrainFactory

Frequency density = Frequency divided by class width. After you've found the freq. dens. for each class interval. Label y 'frequency density' then draw the bars. Suppose 11-19 is a class interval, and 16 is the frequency. The bar would go up 2 (16 divided by (19-11)). and it would be very wide (from 11- 19 on the x axis)

(edited 13 years ago)

Reply 3

hissyfit

OP

15

Original post by BrainFactory

Frequency density = Frequency divided by class width. After you've found the freq. dens. for each class interval. Label y 'frequency density' then draw the bars. Suppose 11-19 is a class interval, and 16 is the frequency. The bar would go up 8 (16 divided by (19-11)). and it would be very wide (from 11- 19 on the x axis)

Thanks for the reply :biggrin:

This is gonna sound really stupid but how do I get the frequency from the table :s-smilie:

Reply 4

BrainFactory

Original post by hissyfit

Thanks for the reply :biggrin:

This is gonna sound really stupid but how do I get the frequency from the table :s-smilie:

The figures that are not bold show the frequencies.

Reply 5

hissyfit

OP

15

Original post by BrainFactory

The figures that are not bold show the frequencies.

So for the 1st one I do 30/(79-70)
or do I divide it by (139-120)
Sorry I m really clueless.

(edited 13 years ago)

Reply 6

aliakhtar

Attache the graph for you. Add in labels and I think that's correct

OP

Original post by BrainFactory

The figures that are not bold show the frequencies.

Can you please check the graph aliakhtar put up please.Thanks

Method thanks to aliakhtar :thumbsup:

You'd need to find out frequency density for each one which is basically Frequency/Class width

The class width of the first one is 120-139 so the width is 19.

The frequencies for the class 120-139 are : 13,14,17 ( Non-bold)

So the frequency density for those would be 13/19, 14/19 and 17/19. You'd plot the classes on the x-axis and the frequency density on the y-axis. Under the class 120-139 you would draw three bars in three different colors showing the the three different pressures. You'd make a key for the diastolic pressure each color shows. Make sure the bars are stacked together with no spaces in between.

(edited 13 years ago)

Reply 8

aliakhtar

Original post by hissyfit

Can you please check the graph aliakhtar put up please.Thanks

Method thanks to aliakhtar :thumbsup:

You'd need to find out frequency density for each one which is basically Frequency/Class width

The class width of the first one is 120-139 so the width is 19.

The frequencies for the class 120-139 are : 13,14,17 ( Non-bold)

So the frequency density for those would be 13/19, 14/19 and 17/19. You'd plot the classes on the x-axis and the frequency density on the y-axis. Under the class 120-139 you would draw three bars in three different colors showing the the three different pressures. You'd make a key for the diastolic pressure each color shows. Make sure the bars are stacked together with no spaces in between.

Correction : There would be no frequency densities as the last class has no width ( > or something . That's why in my graph I just plotted normal frequencies. Other than that I think my method is correct.

Reply 9

BrainFactory

Original post by hissyfit

Can you please check the graph aliakhtar put up please.Thanks

Method thanks to aliakhtar :thumbsup:

You'd need to find out frequency density for each one which is basically Frequency/Class width

The class width of the first one is 120-139 so the width is 19.

The frequencies for the class 120-139 are : 13,14,17 ( Non-bold)

So the frequency density for those would be 13/19, 14/19 and 17/19. You'd plot the classes on the x-axis and the frequency density on the y-axis. Under the class 120-139 you would draw three bars in three different colors showing the the three different pressures. You'd make a key for the diastolic pressure each color shows. Make sure the bars are stacked together with no spaces in between.