Hypothesis 1:
Boys in year 7 will weight less than in year 9 as they would have grown a substantial amount and therefore put on some weight and would be entering puberty in which boys bodies enlarge due to puberty so they will be bigger and heavier.
This hypothesis is very simple and basically is saying that in year 9 the boys will weight more than they did in year 7. This would be due to them growing both taller and therefore heavier. I have decided to only use years 7 and 9 in this as if I had also used 8 the change in weight would not be as big so my results should be bigger and show a larger difference and at year 9 puberty will b at its peak so boys will be a their heaviest.
There are 151 boys is near 7 so I will randomly pick 15 boys in the year for my working and in year 9 there are 145 boys so I will also take 15 boys as in both cases they are 10% of the year group.
Any anomalies that I find in my sampling like for example as boy who weighs 5kg, I will discharge his reading and take another one as if I had taken the very low result then it would put all my results at risk and pull the averages down and may mess up my results.
For this hypothesis I am going to firstly plot all the results of the people I have sampled and find out the mean weight for them all so then I can already see if my hypotheses were right.
Then I will plot one graph with weight of both the years and I will join them up and if my prediction is right then the line for year 9 will be significantly higher than that of year 7.
I will then do box plots to see if the ranges in the years do have a large effect over all as if the ranges on both sides are both big then the graphs will be wider spread and harder to see if my hypothesis are right.
Weight in KG’s.
AS you can already see there is a 12kg increase in the weight of the boys as they have grown up over the 2 years.
Below I will try to show all the readings on a graph to illustrate it as Cleary as possible.
This graph does help us as we can see that the lowest weighing pupil in year 9 is nearly as much as the heaviest in year 7 so that we can see an obvious increase in the weight with the boys.
Finally I am going to find out the how much the range was in the results. To do this I have to find out the upper and lower quartiles for year groups as well as the max weight and min weight and the median to plot on my box plots.
Here are the results I got from my sampling:
As I can see the maximum and minimums are lower in year 7 as 9 which was part of my prediction and the UQR and LQR are both close together so it looks like there were no anomalies and my hypothesis was after all correct.
To conclude this hypothesis, I was right with my prediction and I have shown how I was right and tried to make it as clear as possible.
Hypothesis 2:
Boys in year 7 will be shorter than in year 9 as they would have grown a substantial amount and therefore be a little taller and would be entering puberty in which boys bodies enlarge due to puberty so they will be bigger and taller.
Again for this I will sample the same 30 people as I had in the hypothesis above but will only be interested in height increase. If my hypothesis is right like my first was then I would get the same kind of results as I had for my first one.
I will show you all the heights of the pupils and the average height and then plot then on a graph to see if there was a blatant increase in the height and I will finish it again with a box plot like shown above.
Height in CM’s.
As you can see again there is a 13cm gap in height for the two year groups so, so far again my hypothesis has been correct.
Below I will plot the data onto a graph to see how much the differences are and if there are any large effecting figures.
I can see again that the year 9’s is taller than year 7 but the difference does seem to be quite close and caused by only a few people. I can find out if this is right by doing box plots.
This time you can see that the ranges are more extreme causing the results be look bigger than they are.
To conclude for both hypotheses so far, as you get older, from year 7 to 9, you get both taller and heavier due to the start of puberty.
Hypothesis 3:
Girls encounter puberty at a younger age to boys therefore mature younger so girls in year 9 will be taller than boys in year 9 as the girls would have completed puberty and be fully developed while the boys are just starting the process.
This hypothesis will need me to this time take girls height data and compare it with the data I have already randomly selected for my year 9 boys. I will plot exactly the same ways I previously and will see if I am right.
I was wrong this time with my theory and boys still dominated over the girls even thought the girls had completed puberty and the boys were in the early stages. The average could be lower for the girls as few individuals may have brought the average down for them or a few tall boys may drastically brought it up for the boys. I will try to see if this is true by plotting the graph and to see if there is any wild reading that could have caused this.
This graph does back my point as the boys have 5 people who are taller than the rest by a large area and the girls seem to be quite consistent but some are short bringing down the average. Some of the girls thought are taller than the boys and the heights, even thought the average says is largely different, it looks quite close and may be caused by a few individually tall pupils.
Again I will use a box plot to see if what I had thought bout the few pupils making the difference was right.
I can see from here that the range in height for girls is slightly higher than boys and the is as there is one tall girl and a few shorter ones bringing down the size and the boys are more tighter and constant as you can see above on the box plot.
To conclude I was wrong with this hypothesis as the boys were taller and this may have been because a few shorter girls pulled the average down quite a lot.
Hypothesis 4:
I have decided against my first thought for my forth hypothesis as the boys were already taller than the girls by year 9 so come year 11 the boys would just be even more developed and that much more bigger than the girls as they would have stopped growing.
I decided to change my hypothesis to that there is a positive correlation with height and weight with pupils in the school.
For this is much harder than my other hypothesise and I will have to have to sample randomly 50 pupils are it is 10% of the 552 pupils in year’s 7 and 8. It wont matter is there are more boys than girls, or year 7’s than 8’s. This is because if I am the graph will look like the one below and from it I can see what the approximate weight would be of a pupil if I only no his height or visa versa.
As you can see I have plotted all my reading and there is a positive correlation so I could use this to find out the weight from only knowing the height. There are some of the points plotted the are too high or too low and that is because the person may be anorexic or fat. The red area is my prediction for the safe area for you.
To conclude I was right in saying there would be a relationship between the two and you can clearly see this from the graph.
Overall Conclusion:
I have taught a lot from doing this coursework and that is that both height and weight increase as we grow older until we stop growing which is around year 11 for boys and 9 for girls. I have also learnt that height and weight both have a positive correlation and I have put my own safe area for people to be in for them to be healthy and good weight for their height.