Statistics 1

  1. Data
    any unordered list
  2. information
    list ordered in some way
  3. Two types of statistics
    Descriptive or inferential
  4. descriptive statistics
    • when large amounts of data that must be summarised and presented to the public in a way people can understand
    • eg bar charts, pie charts, averages
  5. inferential statistics
    when statisticians try to predict or forecast based on responses from a small group
  6. types of data
    categorical and numerical
  7. types of categorical data
    • ordinal (can be ordered)
    • nominal (cannot be ordered)
  8. types of numerical data
    • continuous (can be one of an infinite number of values within a given range)
    • discrete ( certain/definite values)
  9. primary data
    is collected by or for the person who is going to use it
  10. two types of primary data
    observational study and designed experiment
  11. observational study
    • researcher collects the information of interest but does not influence the events
    • include case-control studies where one group is the control and the other has the condition
  12. designed experiment
    • treatment applied to a group of subjects and then observe the effects of the treatment on the subjects
    • explanatory variable; the variable being tested
    • response variable; the effect of the variable
  13. sample survey
    opinion polls which are designed to ask questions of a small group of people in the hope of learning something about the entire population
  14. population
    entire group being studied
  15. census
    is a survey of the whole population
  16. sample
    is a group that is selected from the population in order to gather information
  17. parameter
    is a numerical measurement describing some characteristics of a population. It is a fixed number, but in practice its value is unknown
  18. statistic
    is a numerical measurement describing some characteristics of a sample. The statistic can change from sample to sample.
  19. bias in sampling
    • samples that are not representative of the population
    • eg voluntary response samples
  20. simple random sample
    a sample of sizeĀ n is selected in such a way that every possible sample of sizeĀ n from the population has an equal chance of being selected
  21. to select a stratified random sample,
    first divide the population into at least two different subgroups so that the individuals or subjects within each subgroup share the same characteristics. Then a simple random sample is drawn from each subgroup and combined to form the full sample
  22. systematic random sample
    • 1.Assign numbers to population
    • 2.population/sample to find interval
    • 3.choose number between one and the interval (eg interval is 20, and the number is chosen is 13) Start from 13 and select every 20th number from 13
Card Set
Statistics 1
statistics theory