Statistics Coursework
The weight of Jacob’s 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 Jacob’s 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 Jacob’s brand. This is because I
believe that the McVitie’s brand will use more chocolate and more marmalade inside their jaffa cakes than
Jacob’s because Jacob’s brand is slightly cheaper. I think that the Jacob’s jaffa cakes will also have a less
consistent weight that the McVitie’s brand because the difference in price suggests that the production
techniques in the McVitie’s brand may be more consistent than those of the Jacob’s brand.
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,
picked at random from the rest of the population.
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.