A population may contain separate groups or strata. Each group needs to be fairly represented in the sample. The number from each group is proportional to the group size. The selection is then made at random from each group, this is called stratified sampling, and I need to use this to make sure my results represents each group fairly, the equation I need to use is:

No. Of pupils in specific data X Sample No.

Total No. Of pupils

Stratified Sampling

Yr 10 boys= 106/ 370 X 60= 17

Yr 10 girls= 99/370 X 60= 15

Yr 11 boys= 84/370 X =14

Yr 11 girls= 86/370 X 14

Boys= 17+14=31

Girls= 15+14=29

Now from this I will randomly pick my sample of 60 pupils because it is big enough to represent the whole school, I will do this using my calculator by pressing 370Ran# this will give me a random number in decimals I will then round it off.

If a number comes up more than once I will ignore it. I will now keep going until I have a full set of data.

Collecting The Data

As I have already mentioned in my introduction, I will use a sample of 60 students. Upon using the random sampling sample. I realised that I would need 31 boys and 29 girls to fairly represent each group.

Boys

Height Weight

1.9 70

1.6 50

1.6 47

1.68 59

1.8 72

1.77 59

1.72 62

1.75 45

1.75 57

1.57 49

1.73 57

1.54 54

1.63 56

1.61 56

1.65 47

1.65 55

1.6 51

1.67 66

1.72 51

1.65 42

1.69 5

1.75 60

1.7 72

2 60

1.86 80

1.51 38

1.57 54

1.61 45

1.5 45

1.52 44

1.62 51

Here are all the boys to be included in my...

## Again?

You've obviously put some time and effort into documenting the results of your investigation. Your report could have benefited from a clear statement at the very beginning as to the purpose of your investigation. You need to capitalize the title of your paper. It would be advisable to delete references to pages containing diagrams (e.g., scatter diagram, histogram and box plot) which have not been provided. Commendable effort! This is now the third time this information has been provided, although I note the slight change in your title.

8 out of 8 people found this comment useful.