Organising and interpreting data

• Primary data


  Collected first-hand by a researcher

  eg. through experimentation, observation or survey
• Secondary data


  Sourced from others' prior research

  eg. through accessing data from publicly available databases or using other data that other researchers have previously collected
• Quantitative data


  Expressed numerically

  eg. test scores or measurements of weight
• Qualitative data


  Expressed non-numerically

  eg. a participant's verbal description of how they are feeling
• Objective data


  Observed and measured independently of personal opinion

  eg. a person's weight in kgs or numerical scores on an intelligence quiz
• Subjective data


  Informed by personal opinion, perception or interpretation

  eg. qualitative descriptions by a researcher or participant and self reports
• Processing data 


  Descriptive statistics describe, organise and summarise a study's data
• Percentages


  Makes it easier to notice patterns and trends
• Percentage change


  Useful for making comparisons between conditions or groups
• Mean


  Measure of central tendency that describes the numerical average of data sets

  -Helpful to tell a researcher what the typical response or score is

  -Less helpful when data values are widely distributed (because the data set is likely to be influenced by extreme values and outliers)
• Median 


  Measure of central tendency that is the middle value in a data set ordered from lowest to highest

  -Helpful to identify a more typical response when the data is not evenly distributed around the centre or when there are outliers
• Mode


  The measure of central tendency that is most frequently occurring value in a data set

  -Helpful to identify the most common and frequently occurring value
• Measures of variability 


  Statistics that summarise and describe the spread and distribution of a data set

  -Range

  -Standard deviation
• Range


  Measure of variability that is a value obtained by subtracting the lowest value in a data set from the highest value

  -Helpful to summarise the overall dispersion (distribution) of scores
• Standard deviation 


  Measure of variability expressed as a value that describes the spread of data around the mean (how much data deviates from the mean)

  -Higher standard deviation= the greater the data values in the set differ from the mean

  -Helpful to allow comparisons to be made between different data sets based on their dispersion
• Table


  A presentation of data arranged into columns and rows

  -Helpful to organise data in a more accessible format and show the relationship between certain variables

  -Include header row with unit and title
• Bar Charts 


  Displays the relationship between at least two variables using rectangular bars with heights or lengths proportional to the values they represent

  -Used for categorical data

  -Must follow graphing conventions
• Line graphs 


  Displays the relationship between at least two variables using a straight line to connect data points

  -Used for continuous data

  -Must follow graphing conventions