As soon as I finalised my sample which represented the year 7 boys I put the data in a table, as followed -
The table consisted of the height and weight of the boys in year 7 that made it to the sample.
I then decided to work out the average height of the boys in year 7 who were on the sample. The first average I decided to use was a “Mean” average, which is found by adding all the items of data and dividing this value by the number of items of data. I then took the heights of the boys in year 7 who were on the sample and added them all together -
1.48
1.5
1.36
1.73
1.52
1.62
1.43
1.5*
1.51
1.44
1.49
1.61
1.5
1.45
1.65
1.59
1.65
1.49
1.48
____
29
____
I then divided the answer (29) by the number of items of data (19)
29
___
= 1.526315789
19 (1.53)
I then decided to find the median, which is simply the middle item of data. To find the median I wrote the items of data in numerical.
I then noticed that 1.50 was the median, simply because it was in the middle.
As the appropriate items of data are now in numerical order, it would be idea to find the range, which is one single number and it's the difference between the lowest and highest value of the data. The lowest item of data being 1.36, and the highest being 1,73, therefore -
1.73
1.36
____
0.37
____ Range = 0.37
I then worked out the average weight of the boys in year 7 who were on the ample. I initially decided to work out the “mean” average. Firstly I took the weights of the boys in year 7 who were on the sample and added them all together -
44
41
45
53
32
48
33
50
45
42
47
56
51
31
51
47
46
35
40
___
836
___
I then divided the answer (836) by the number of items of data (19)
836
___ = 44
19
I then decided to find the “median” average, therefore I wrote the items of data in numerical order.
I then noticed that 45 was the median, as it was in the middle.
Next I decided to find the range -
Highest item of data = 56
Lowest item of data = 31
therefore -
56
31
__
25 Range = 25
I then decided to find the “mode”, which is the item of data that occurs most often in the data. To find the mode I decided to draw a “stem and leaf” diagram, as I feel this is the most convenient method of identifying the “mode”.
The following stem and leaf diagram shows the weight of the boys in year 7, who were on the sample -
Weight | Frequency
|
30 | 2315
40 | 4158527760
50 | 30610
|
After observing my stem and leaf diagram, I came to the conclusion that there are 3 “modes” which are 45, 47 and 50.
The next step was to do the exact same process again, however, this time I was investigating the data of the year 7 females. I used the exact same method of sampling as I did previously, which was “systematic sampling”.
As soon as I finalised my sample which represented the year 7 girls I put the data in a table, as followed -
The table consisted of the height and weight of the girls in year 7 that made it to the sample.
I then decided to work out the average height of the girls in year 7 who were on the sample.
The first average I decided to use was a “mean” average.
Firstly I took the heights of the girls in year 7 who were on the sample and added them all together, as followed -
1.56
1.63
1.48
1.59
1.54
1.51
1.31
1.30
1.63
1.59
1.66
1.48
1.43
1.49
1.42
1.48
1.75
1.48
1.42
_____
28.75
____
I then divided the answer (28.75) by the number of items of data (19)
28.75
_____ = 1.513157895
19
I then decided to find the “median” average, therefore I wrote the items of data in numerical order.
I then noticed that 1.49 was the median, simply because it was in the middle.
Next I decided to find the range -
Highest item of data = 1.75
Lowest item of data = 1.30
therefore -
1.75
1.30
____
0.45
____ Range = 45
I then worked out the average weight of the girls in year 7 who were on the sample. I initially decided to work out the “mean” average.
Firstly I took the weight of the girls in year 7 who were on the sample and added them all together -
53
45
39
38
40
50
45
36
51
44
45
34
38
40
52
37
57
47
40
____
831
___
I then divided the answer (831) by the number of items of data (19)
831
___ = 43.73684211
19
I then decided to find the “median” average, therefore I wrote the items of data in numerical order.
I then noticed that 44 was the median, as it was in the middle.
Next, I decided to find the range -
Highest item of dara – 57
Lowest item of data – 34
therefore -
57
34
__
23
__ Range = 23
I then decided to find the mode. To find the mode, I drew a stem and leaf diagram as I feel this is the most convenient method if identifying the “mode” - (most often occuring item of data).
The following stem and leaf diagram shows the weights of the girls in year 7 who were on the sample -
Weight | Frequency
|
30 | 986487
40 | 50545070
50 | 30127
|
After observing my stem and leaf diagram I came to the conclusion that there are 2 “modes” which are “40” and “45”.
