# I intend to investigate the relationship between height and weight

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Introduction

I intend to investigate the relationship between height (M) and weight (Kg) in Mayfield High School. The hypotheses that I have made are effective but simple. I expect to find that: 1) Boys weigh more than girls 2) Girls are taller than boys in KS3 3) When I investigate the relationship between height and weight, I expect to find that the taller you are, the heavier you weigh. 4) Gender may affect the results that I will have attained by the end of my investigation. I possess a secondary source of data that I had obtained on a website www.edexcel.com which had been posted by the examination board. I have chosen to use a secondary source of data, as this data is easier to obtain than raw (primary) data. I am taking in to account that this is a secondary source of information; it could contain faults or could be in some sort of way corrupt. To acquire such raw data, I would have to perform a data research which could take a long period of time depending on the investigation, population size and many other factors. ...read more.

Middle

Stratified sampling is a sampling method in which the population is divided in to groups (in this case, year groups) and then random samples are taken from each stratum (or layer). There are two ways in which you could do stratified sampling. The first method involves dividing the class size by the total population and then multiplying the result by the size of the sample. The second method is dividing the class size by a hundred and then multiplying the result by the percentage size of the sample. The calculations that I will have to do are to find the measures of central tendencies, which are the estimated mean, median, mode and range. In a frequency table, the mean would simply be multiplying the 'mid-interval value' by the 'frequency' for each column. Then find the total of the 'mid-interval value times frequency' column and divide that by the 'frequency column' total to then get the estimated mean. The median is the number in the middle of the whole sequence, presuming that the sequence is set out in ascending order. ...read more.

Conclusion

Tally charts are straightforward to use, it helps with counting and displays the frequency of the groups very clearly. The cumulative frequency graph will make it easier to find the upper quartile, lower quartile, interquartile range, median values of data. The box and whisker diagram will be the best possible way to present that data. The scatter graph is the best way to show how two pieces of data correspond with each other. It can show if there is a strong positive correlation, a strong negative, a weak positive, a weak negative correlation or if there is no correlation at all. We can gain even more information if we include in a line of best fit, with its equation Y=mx+c. The 'Y' in the equation represents the point in the graph, the 'm' represents the gradient, the 'x' represents another point on the graph and finally the 'c' represents the intercept. We use scatter diagrams mostly to compare two variables. As a result of the calculations and diagrams I intend to produce, I will be able to compare and analyse the recorded data to prove or disprove my hypotheses. ?? ?? ?? ?? Maths Coursework Rujina Miah 10S ...read more.

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