STATISTICAL STATISTICS

• What is qualitative data?

  Descriptive/non-numerical data
• What is quantitative data?

  Data that can be measured numerically
• 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?

  Categories with no particular order
• What is ordinal data?

  Categories with an order
• What is interval data?

  Equal intervals but no true zero
• What is ratio data?

  Equal intervals and a true zero
• What is primary data?

  Data collected directly
• What is secondary data?

  Data drawn from previously collected sources
• What is a population in data collection?

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

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

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

  Not a whole population
• What is a sampling frame?

  A list of people chosen for sampling
• What is nominal data used for?

  • Groups similar qualities
  • Data is categorized by qualities
• How do you find the nth interval in systematic sampling?

  Population size / sample size
• How is stratified sampling conducted?

  Proportional to the size of each group
• What is random sampling?

  Random selection to avoid bias
• What is frequency density in histograms?

  Frequency / Class width
• What is cumulative frequency for discrete data?

  • Sum of all frequencies for that class
  • Includes all preceding classes
• What is cumulative frequency for continuous data?

  • Total frequency of values less than or equal to the upper class boundary
  • Used for unified data class charts
• What do comparative pie charts do?

  • Compare proportions of data
  • All pie charts should be the same size
  • Larger segments indicate more frequent values
• What are scatter diagrams used for?

  • Bivariate data representation
  • X-axis: Independent variable
  • Y-axis: Dependent variable
• What is positive correlation in scatter diagrams?

  Change in one variable causes change in another
• What is negative correlation in scatter diagrams?

  Change in one variable causes opposite change
• What does correlation show?

  Link between two variables, not causation
• What is the equation of the line of best fit?

  y = mx + c
• What is extrapolation?

  Extending the LOBF beyond plotted data
• What is a regression line?

  A more accurate line of best fit
• What is the equation of the regression line?


  y = a + bx
• What is the range in measures of dispersion?

  Largest value - smallest value
• What is the interquartile range (IQR)?

  Upper Quartile - Lower Quartile
• What is the lower quartile (Q1)?

  1/4th value
• What is the semi-interquartile range?

  IQR / 2
• What is standard deviation?

  Measure of how far values are from the mean
• What is the mean in measures of central tendency?

  Most common value
• What is the upper quartile (Q3)?

  3/4th value
• What is the median?

  Middle value
• What is the mode?

  Class with the highest frequency