956 words - 4 pages

The Relationship between Height and Weight 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 ...view middle of the document...

I will then use the data

that I have acquired after using the stratified sampling to select the

number of pupils randomly and hopefully prove or disprove the

hypotheses that I have made.

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. The mode is

the number which appears the most in the sequence. The range is merely

the difference between the highest number and the lowest number.

Also two other calculations that I will carry out are standard

deviation and Spearman’s rank correlation. Standard deviation is the

square root of the measure of spread that uses all the data.

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Spearman’s rank correlation coefficient is a measure of the agreement

between two that has been data set. However it can also be...

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