This document summarizes a student project comparing the costs of mobile phones and contracts from two retailers, Phones 4 U and Carphone Warehouse. The student gathered specifications for several phones, compared monthly tariffs for contracts, calculated total costs over 24 months, and analyzed their own phone usage. Based on lower prices at Carphone Warehouse and sufficient storage, the student concluded the iPhone 5c would be the best choice.

1. Page 1 of 6
In this project I am going to compare the cost of a number of mobile phones from two
different retailers, ‘Phones 4 U’ and ‘Carphone Warehouse’.
In this I will be gathering information to decide on the most suitable phone and contract.
I will be working out the average costs for the different phones and price plans, considering
whether the mean, median or mode gives the most realistic result.
I will use a pie chart to work out and show my personal phone usage and a formula to
calculate the cost of at least two different price plans over the course of an average contract
length which is 24 months.
Finally I will decide which phone and price plan would be best suited to me.
How mobile phones work
In my research I found various charts that I have bookmarked on Diigo, such as a diagram
showing how a mobile phone is able to communicate and access the internet wirelessly;
All mobile to mobile calls have to go through a mobile switching centre, which is a service
delivery node; this allows people to communicate wirelessly. This is also the same for
accessing the internet via a smartphone.
The mobile phone first sends information to a base station which in turn sends this through
a mobile switching centre server using a fixed microwave link, which uses radio waves to
transmit information. This allows access to the internet sending the information back to your
phone.
Here is a link to a diagram that explains this in a visual way:
http://4.bp.blogspot.com/-oHcAJePeZ8o/T2sud_-
dsyI/AAAAAAAAAI0/LTmm0mjFoG4/s1600/basic+cellular+network.jpg

2. Page 2 of 6
Specification comparison
I compared 10 phones from the Carphone Warehouse supplement, ‘The Guide’ issue 2.
Model
Operating
System
Battery
life
Out of 5
Processor
Speed
Out of 5
Camera
Megapixels
Screen
quality
Out of 5
Screen
size
(inches)
Blackberry
9720
Blackberry OS
7.1
1 1 5 1 2.4
LG Optimus
L3 II
Android 4.1
Jelly Bean
2 1 3.15 1 3.2
HTC Desire
500
Android 4.1
Jelly Bean
2 3 8 2 4.3
HTC One Android 4.1
Jelly Bean
2 4 4 4 4.7
Sony Xperia M Android 4.1
Jelly Bean
3 2 5 2 4
Blackberry
Z30
Blackberry OS
10.2
3 3 8 3 5
Sony Xperia Z
Ultra
Android 4.2
Jelly Bean
3 5 8 5 6.4
Nokia Lumia
1020
Windows
Phone 8
4 3 41 3 4.5
LG G2 Android 4.2
Jelly Bean
4 5 13 4 5.9
Nokia Lumia
1520
Windows
Phone 8
5 5 20 4 6
As battery life and megapixels are both important to me I decided to filter these phones to
show greater than and equal to 3 out of 5 for battery life and 8 for megapixels. I did this
using the AutoFilter tool in Excel.
Below are the results:
Model
Operating
System
Battery
life
Out of 5
Processor
Speed
Out of 5
Camera
Megapixels
Screen
quality
Out of 5
Screen
size
(inches)
Blackberry
Z30
Blackberry OS
10.2
3 3 8 3 5
Sony Xperia Z
Ultra
Android 4.2
Jelly Bean
3 5 8 5 6.4
Nokia Lumia
1020
Windows
Phone 8
4 3 41 3 4.5
LG G2 Android 4.2
Jelly Bean
4 5 13 4 5.9
Nokia Lumia
1520
Windows
Phone 8
5 5 20 4 6

3. Page 3 of 6
Price comparison
Below is a table which consists of 5 different phones and tariffs from Carphone Warehouse:
Phone Memory Cost of Phone Monthly Tariff Minutes Texts Data
iPhone 4s 8GB Free £22.00 200 Unlimited 100mb
iPhone 5s 16GB Free £42.00 Unlimited Unlimited 1GB
iPhone 5c 16GB Free £32.00 Unlimited Unlimited 1GB
Nokia Lumia 1020 32GB Free £37.00 600 Unlimited 750mb
Next is a table that shows the same phones from Phones 4 U:
Phone Memory Cost of Phone Monthly Tariff Minutes Texts Data
iPhone 4s 8GB Free £27.99 1000 Unlimited 500mb
iPhone 5s 16GB Free £47.00 Unlimited Unlimited 6GB
iPhone 5c 16GB Free £33.00 Unlimited Unlimited 1GB
Nokia Lumia 1020 2GB (with
optional
memory
via an SD
card)
Free £42.00 Unlimited Unlimited 6GB
Now that I have collected this data I will work out the mean, median and mode for all phones from
both retailers:
Mean Median Mode Range
Monthly tariff £35.37 £35.00 £42.00 £25.00
As these pay monthly contracts include a free phone and unlimited amounts of minutes and data,
working out the mean, median and mode wasn't entirely possible, though both the mean and
median of the monthly tariff is useful as it gave me an estimated average price that I would be
expected to pay per month.

4. Page 4 of 6
Mobile Phone Usage
Now I will work out my estimated phone usage and represent this as a pie chart:
During the daytime I am at work so my phone usage is very low I have a 15 minute break in the
morning and a 30-60 minute break for lunch, though I do not always use my phone in these times
so I added the 15 to the 60 to make 75, halving this then rounding it up to 40 minutes per day.
In the evening I would say around 2 hours of my time may consist of phone usage including text
messaging, phone calls and internet data.
At the weekend is when I would use a mobile phone the most. So I estimated around 5 hours per
day, meaning 10 hours over the 2 day period.
This information would be useful if I wanted to buy a “Pay As You Go” phone as, unlike contract
phones, I would need to pay for length of calls and data usage.

5. Page 5 of 6
Contract Cost Comparison
Over the course of a 2 year contract where: B=Total Bill and T=Monthly Tariff ∴ B=24T
Using this formula with a calculator I worked out how much a 2 year contract would cost and compared 3 of the mobile phones from both
companies.
iPhone 4s (Carphone Warehouse)
T=22
B= 22*24= £528
iPhone 4s (Phones 4 U)
T=28 (rounded to nearest £)
B=28*24= £672
iPhone 5c (Carphone Warehouse)
T=32
B=32*24=£768
iPhone 5c (Phones 4 U)
T=33
B=33*24=£792
Nokia Lumia (Carphone Warehouse)
T=37
B=37*24=£888
Nokia Lumia (Phones 4 U)
T=42
B=42*24=£1008
Total bill (24 month contract)
Percentages Cost Difference
I then worked out the total bills as
percentage difference and simple fractions:
iPhone 4s
Phones 4U = £672
Carphone Warehouse = £528
= (672-528)/672 * 100
= 264/672 * 100
= 0.2142857 * 100
= 21.428571% rounded down to 21%
iPhone 4s is 21% cheaper at Carphone
Warehouse (or approximately one fifth
cheaper = 1/5)
iPhone 5c
Phones 4U = £792
Carphone Warehouse = £768
(792-768)/792=0.030303
*100=3.030303
=3.03% rounded down to 3% difference
iPhone 5c is 3% cheaper at Carphone
Warehouse (or one thirty-third cheaper =
1/33)
Nokia Lumia
Phones 4U = £1008
Carphone warehouse =£888
= (1008-888)/1008 * 100
= 120/1008 *100
= 0.11904761
= 11.904761% rounded up to 12%
Nokia Lumia is 12% cheaper at Carphone
Warehouse (or one eighth cheaper = 1/8)

6. Page 6 of 6
Conclusion
Overall I have concluded that Carphone Warehouse is cheaper than Phones 4U in
every case, when buying a contract phone.
The Nokia Lumia 1020 would be more beneficial as it has the capacity to increase its
memory size via SD card and also has a far superior camera. However this is the
most expensive option at £2 per month more than the average.
The iPhone 4 would be the cheapest option and would work collaboratively with my
iPad and any existing in app purchases which would mean I would not have to pay
for them again as with the Nokia Lumia 1020 which is Windows based. However for
iPhone 4 is only available with 8GB of memory.
Which means the phone of choice would be the iPhone 5c as it has 16GB which
should be enough memory for a decent amount of apps, photos and songs and is
still cheaper than the average by £2 per month.