Stats

• Types of data


  Primary

  Secondary

  Qualitative

  Quantitative

  Continuous

  Discrete

  Categorical

  Ordinal

  Bivariate

  Multivariate
• Sampling key terms

  Population

  Census(survey of the whole population)

  Sample

  Biased sample

  Sampling frame (list of items that are to be sampled)
• Random sampling


  Everyone has an equal chance

  1. Number everyone in population
  2. Random number generator for sample size
  3. Match numbers to individuals
  4. Ignore repeats/numbers outside the range
• Stratified sampling


  Split into strata's (groups)

  Also use RNG.

  Number of strata=(strata size÷total population) x100
• Systematic sampling 


  Every nth interval

  To find nth interval=population size ÷sample size
• What are the two main types of data?

  Qualitative and Quantitative
• What is qualitative data?

  Data that is descriptive
• What is quantitative data?

  Numerical data
• What is discrete data?

  Data that can only take particular values
• What is continuous data?

  Data that can take any value within a range
• What is nominal data?

  Data put into categories
• What is ordinal data?

  Data that can be ordered
• What is interval data?

  Data with equal intervals
• What is ratio data?

  Data with equal intervals and a true zero
• What is primary data?

  Data collected for the first time
• What is secondary data?

  Data collected by someone else
• What is a population in research?

  Everything or everybody included in the study
• What is a sample?

  A smaller number of items from the population
• What is a census?

  A survey of the whole population
• What is a sample survey?

  A survey of a sample from the population
• What is a sampling frame?

  A list of people to be sampled
• What are the types of sampling methods?

  • Systematic Sampling
  • Stratified Sampling
  • Random Sampling
  • Non-random Sampling
• How do you find the nth interval in systematic sampling?

  Population size / Sample size
• What is stratified sampling?

  Proportions of each group match population size
• What is random sampling?

  Random selection of samples from the population
• What is non-random sampling?

  Sampling methods that do not use random selection
• What is convenience sampling?

  Using readily available data
• What is quota sampling?

  Selecting a set number of each group
• What is opportunity sampling?

  Selecting who is available
• What is the formula for frequency density in histograms?

  Frequency Density = Frequency / Class Width
• How is cumulative frequency represented for discrete data?

  Height of each bar represents frequency
• How is cumulative frequency represented for continuous data?

  Area of each bar represents frequency
• What are the requirements for comparative pie charts?

  • Same size pie charts
  • Must have the same total
  • A key is important
• What type of data do scatter diagrams use?

  Bivariate data (independent/dependent variable)
• What does the x-axis represent in scatter diagrams?

  Independent variable
• What does the y-axis represent in scatter diagrams?

  Dependent variable
• What is positive correlation?

  One variable increases as the other increases
• What is negative correlation?

  One variable decreases as the other increases
• What does no correlation mean?

  No clear pattern between the variables
• What does correlation not imply?

  Correlation does not imply causation