Acknowledgements First of all, I would like to thank God for giving me the life and good health needed to carry out this dissertation. I would also like to thank my teacher Mrs. Scott for giving me guidance in putting together this SBA. Moreover I am very grateful to the staff of the JnMarie & Sons Ltd. for providing me with the necessary information. In particular, I would like to thank the co-owner, Mr. Everistus Jn- Marie, for not only providing me with information but answering my questions and queries. Finally, I would like to thank my parents, for providing me with the resources needed to complete this SBA. 1 | Page
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Acknowledgements
First of all, I would like to thank God for giving me the life and good health needed to
carry out this dissertation.
I would also like to thank my teacher Mrs. Scott for giving me guidance in putting
together this SBA.
Moreover I am very grateful to the staff of the JnMarie & Sons Ltd. for providing me
with the necessary information. In particular, I would like to thank the co-owner, Mr. Everistus
Jn-Marie, for not only providing me with information but answering my questions and queries.
Finally, I would like to thank my parents, for providing me with the resources needed to
complete this SBA.
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Introduction
JnMarie & Sons is a private limited company that was formed in 1977 by Raphael Jn-Marie. The
gas station has two branches in Castries, one on Manuel Street and the other on the John
Compton Highway.
One of the products that JnMarie & Sons sells is Liquefied Petroleum Gas (LPG) which is more
commonly known as cooking gas. The business orders LPG in large 6000 lb cylinders called
Iso-Tanks and then transfers it to smaller 20 lb cylinders for sale.
One Iso-Tank costs $21,710 whilst the company sells each 20 lb cylinder at $39.60.
The Iso-Tank is supposed to fill a total of 1,300 smaller 20 lb cylinders. However, the gas station
often gets more or less than this proposed amount of gas.
Therefore, the question is, on average, does an Iso-Tank fill 1,300 smaller 20 lb cylinders? This
project is aimed at answering this question.
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Purpose and Aims
The main purpose of this project is to find out whether if, on average, a 6000 lb cylinder of LPG
ordered by JnMarie & Sons fills the correct amount of 20 lb cylinders.
The project has the following aims:
To use a hypothesis test to determine whether or not, on average, an Iso-Tank of LPG
fills 1,300 smaller 20 lb cylinders.
To estimate a 95% confidence interval for the mean amount of 20lb cylinders that are
filled from an Iso-Tank.
To identify outliers in the iso-tank outputs and investigate the reasons for the existence
of these outliers.
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Variables
1. Iso-Tank Output (No. of 20lb Cylinders)
The number of 20 lb cylinders filled from each iso-tank varies from tank to tank.
Factors Affecting Iso-Tank Output
Below are several factors that can affect the number of 20 lb cylinders filled from a 6000
lb tank. These are:
i. Leakages
Leakages of the 6000 lb tanks can occur during transit or whilst the gas is being
transferred to the 20 lb cylinders. Significant leakages would result in less 20 lb cylinders
being filled.
ii. Theft & Sabotage
Employees or other personnel can steal gas from 6000 lb tank for their personal use or
to sabotage the company. This would reduce the number of 20 lb cylinders filled.
iii. Amount of LPG Left in Returned Tanks
If cylinders received from customers for replenishment has some unused product then it
would take less gas from the Iso-Tank to fill the 20 lb cylinder. Hence, more gas will be
available to fill other tanks, which may cause the output being of 1300 cylinders.
iv. Manufacturing Procedures
The process used to fill the 6000 lb tanks by the manufacturer will affect the number of
filled 20 lb cylinders received by Jn Marie. If the manufacturing procedures are good and
consistent, then the correct amount of gas should be obtained in most 6000 lb cylinders.
However, if it is faulty, greater or lesser amounts may be placed into the 6000 lb
cylinders.
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Unfortunately, it was not possible to control any of the above mentioned factors.
NB: Errors made by employees in counting the number of cylinders can also cause the iso-
tank output to vary.
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Data Collection
1. Method of Data Collection
The method used was documentary research. Co-owner of the firm, Mr. Everistus Jn-
Marie had the most recent figures written on a board in his office. Hence, on Monday
10th March 2014, I went to his office and took down these figures by hand.
It would have been much too impractical to collect the data directly. This is because it
would take a significant amount of time to count thousands of 20 lb cylinders.
Moreover, the gas station does not order several 6000 lb tanks at once, but once every
week. Therefore, in order to obtain a sufficiently large sample of 30 measurements it
would take 30 weeks.
However, the process used by employees to count the number of filled tanks is
explained below:
At the filling area, empties are counted before filling begins.
They are batched according to their tare weight (weight of an empty tank).
The scale is set accordingly and the tanks are filled, two tanks at a time.
E.g. If a tank has a tare weight of 25 lbs and 20lbs of product needs to be placed
into it then the scale is set at 45lbs during filling. The filling of the tank will
automatically cease at the weight of 45lbs.
2. Sampling
Quota sampling was used mainly due to the time constraint. The sample used was the
set of figures obtained from the board in Mr. Jn-Marie’s office. These figures were the
67 most recent counts of the number of 20 lb cylinders filled from a 6000 lb tank.