Harry Webster
Stats Coursework Introduction – First Draft
Statistics Coursework
The weight of Somerfield’s own Jaffa Cakes versus the weight of McVitie’s Jaffa Cakes
Introduction
Aim
I aim to compare data from two populations in order to prove my hypothesis. In this project the two populations
are Somerfield’s own brand of jaffa cake and also McVitie’s brand of jaffa cake. The data I am going to analyse
is the weight of the two different brands. I am going to take a population of 150 jaffa cakes from each brand and
use these in my calculations and to prove my hypothesis.
Hypothesis
My hypothesis is that McVitie’s will have a slightly heavier weight than the Somerfield’s own brand. This is
because I believe that the McVitie’s brand will use more chocolate and more marmalade inside their jaffa cakes
than Somerfield because Somerfield’s brand is cheaper. I think that neither Somerfield jaffa cakes nor McVitie’s
jaffa cakes will vary greatly in weight and therefore will have similar standard deviations. This is because the
production process of both companies will be fairly similar and both processes will make jaffa cakes at
consistent weights.
Sampling Techniques
I am going to use a systematic sampling method to decide which of the 150 jaffa cakes I will use in calculations
to prove my hypothesis. I shall select every third jaffa cake out of the 150 in order to have 50 jaffa cakes to use
in calculations. This is a good method to use because the jaffa cakes are all similar and therefore do not require
a random sampling method. Also, this method will is more appropriate than a stratified sampling method
because I have an equal number of jaffa cakes in each population.
Assumptions
I shall be measuring the jaffa cakes on a digital scale in grams to 2 decimal places. If a jaffa cake is broken I
shall not use it because this may have affected the weight of it, instead I shall draft in a replacement jaffa cake.
Calculations
I shall use both mean and standard deviation calculations to find out on average which jaffa cake brand weights
more on average and if (as stated in my hypothesis) they both are reasonably consistent in weight.