Types-Of-Data gcse Edexcel

Types of Collected Data

What types of data do I need to be familiar with?

• There are a number of terms for types of data that you need to be familiar with

  • You need to recognise and understand them when they appear in exam questions

  • And be able to use them when writing your answers to questions

• Raw data is data in exactly the form that it was collected

  • i.e. before it has been organised or processed in any way

• Raw data can be either quantitative or qualitative

  • Quantitative data can be recorded as a number

    • e.g. heights, lengths of time, numbers of people or objects, shoe sizes, etc.

  • Qualitative data cannot be recorded as a number

    • e.g. colours, flavours, kinds of animal, makes of car, etc.

• Quantitative data can be either continuous or discrete

  • Continuous data can take any numerical value on a scale

    • e.g. height, length, weight, mass

    • For continuous data the measurements can become more and more accurate the more you ‘zoom in’

  • Discrete data can only take on particular numerical values on a scale

    • Often these are integers (e.g. numbers of people or objects)

    • But they don’t have to be integers (e.g. shoe sizes, which include ‘half sizes’)

• Categorical data is data that can be organised into non-overlapping categories

  • ‘Non-overlapping’ is important here

    • Each piece of data can belong to one and only one category

    • e.g. heights less than 1.7 metres () and heights greater than or equal to 1.7 metres ()

    • but not and (because a height of 1.7 metres would belong to both categories)

  • The categories can be numerical or non-numerical

• Ordinal data is data that can be written in order

  • If the data is numbers, these can be ordered in the usual way

  • If the data is not numbers, then it must be possible to apply a numerical ‘rating scale’

    • e.g. a scale of 1 to 5 with 1 as ‘disagree strongly’ and 5 as ‘agree strongly’

• Bivariate data is data that is collected as pairs of values

  • This could be data collected to investigate

    • the relationship between two variables

    • how changes in one variable affect the other variable

  • e.g. age of car and cost of annual maintenance, train ticket price and length of journey, etc.

What is the difference between primary data and secondary data?

• For the exam, you need to know the difference between primary data and secondary data

  • This includes recognising the advantages and disadvantages of each

• Primary data is data that is collected either by the person who is going to use it, or specifically for the person who is going to use it

  • Advantages of primary data:

    • Can be gathered specifically for the question you are trying to answer

    • The level of accuracy will be known

    • The collection method will be known

  • Disadvantages of primary data:

    • Collecting data can require a lot of time

    • It can also be expensive

• Secondary data is data that has been collected by somebody else

  • Some possible sources for secondary data:

    • the internet

    • print media (newspapers, magazines, etc.)

    • databases

    • research articles

    • census returns

  • Advantages of secondary data

    • Can be quicker to obtain (i.e. less time)

    • Can be easier to obtain (i.e. more convenient)

    • Less expensive than collecting data yourself

    • May be more accurate than data you collect yourself (depending on the source)

  • Disadvantages of secondary data

    • May be hard to find relevant data for your specific question

    • The data may be out of date

    • The level of accuracy may not be known (e.g. the data may have been rounded)

    • The collection method may not be known

    • The source of the data may not be reliable

  • If you use secondary data, it is always necessary to acknowledge the source that the data was taken from