# Statistically analyse the data given to me regarding used car sales.

Andreas Poole

Mathematics Coursework

• Strand 1:
Specify clearly what you plan to do and why you are approaching the investigation in this way.

• Strand 2:
Collating the data you need and representing it in a way which helps to develop your investigation.

• Strand 3:
Interpreting your results and drawing conclusions from them.

My task for this coursework is to statistically analyse the data given to me regarding the used car sales. I shall begin with looking at the data. This includes data about 100 used cars, and various other sets of information about the cars such as:

• car,
• make,
• model,
• new price,
• second hand price,
• age,
• colour,
• engine size,
• fuel,
• mpg,
• mileage,
• service history,
• owners,
• length of MOT,
• tax (months),
• insurance group,
• doors,
• style,
• central locking,
• seats, gearbox,
• air conditioning,
• airbags.

Because there is so much data, I will have to sample the data.

In order for my analysis to be more reliable I will use stratified sampling. I have decided to sample 25 cars from the data given to me. In order for me to choose them, I will have to make a frequency table to tell me how many makes and models there are. E.g. how many Ford’s there are in the data? Because I want to sample 25 cars I will use the formula below.

Numbers of cars in each make
4

E.g. If there are 16 Fords, then 16÷4=4.

When this has been done I will use the random function on my calculator or on excel to choose 4 Ford cars at random.

Below is the frequency table of car makes:

Below is all of the data I will be sampling:

Another method of sampling is random sampling. This can be used to obtain a set of 25 different cars to analyse. This is very bias because every car would be given a number using a random number generator. This would make the data bias because an anomaly car would have been included and may have possibly been included many times over therefore making the data unreliable.

### Hypothesis

My first prediction is that when mileage increases, the percentage decrease of the price will also increase. This is ...