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Statistics

Charlotte Allen Englisch 37 Karten

Karten in diesem Stapel (37)

  1. 1What is a population, in statistics? (Yr 1, 1.1)A population is the whole set of items that are of interest
  2. 2What is a census? (Yr 1, 1.1)A census observes or measures every member of a population
  3. 3What is a sample? (Yr 1, 1.1)A sample is a selection of observations taken from a subset of the population which is used to find out information about the population as a whole
  4. 4What is an advantage of a census? (Yr 1, 1.1)It should give a completely accurate result
  5. 5What are the disadvantages of a census? (Yr 1, 1.1)- Time consuming and expensive
    - Can't be used when the testing process destroys the item
    - Hard to process large quantity of data
  6. 6What are the advantages of a sample? (Yr 1, 1.1)- Less time consuming and expensive than a census
    - Fewer people have to respond
    - Less data to process than in a census
  7. 7What are the disadvantages of a sample? (Yr 1, 1.1)- The data may not be as accurate
    - The sample may not be large enough to give information about small-sub groups of the population
  8. 8How can the size of the sample affect the validity of any conclusions drawn? (Yr 1, 1.1)Size of the sample depends on the required accuracy and available resources. The larger the sample, the more accurate however you will need greater resources. Need a larger sample if the population is varied (rather than uniform)
  9. 9Individual units of a population are know as... (Yr 1, 1.1)...sampling units
  10. 10Often sampling units of a population are individually named or numbered to form a list called... (Yr 1, 1.1)...a sampling frame
  11. 11What are the three methods of random sampling? (Yr 1, 1.2)- Simple random sampling
    - Systematic sampling
    - Stratified sampling
  12. 12What is a simple random sample? (Yr 1, 1.2)A simple random sample of size n is one where every sample of size n has an equal chance of being selected
  13. 13How do you carry out a simple random sample? (Yr 1, 1.2)You need a sampling frame, each person or thing is allocated a unique number and selection of these numbers are chosen at random - either by a random number generator or lottery sampling
  14. 14What is lottery sampling? (as part of simple random sampling) (Yr 1, 1.2)The members of the sampling frame could be written on tickets and placed into a 'hat'. Required number of tickets would then be drawn out
  15. 15What is systematic sampling? (Yr 1, 1.2)In systematic sampling, the required elements are chosen at regular intervals from an ordered list
  16. 16How would you carry out a systematic sample for a sample size of 20 from a population of 100? (Yr 1, 1,2)100/20 = 5
    You would select every fifth person
    (The first person to be chosen should be chosen at random though e.g first is 2 so then. 7, 12, 17 etc)
  17. 17What is stratified sampling? (Yr 1, 1.2)In stratified sampling, the population is divided into mutually exclusive strata (e.g males and females) and a random sample is taken from each
  18. 18What is the formula for a stratified sample? (Yr 1, 1.2)number in stratum/number in population
    x overall sample size
  19. 19What are the advantages of simple random sampling? (Yr 1, 1.2)- Free of bias
    - Easy and cheap to implement for small population and small samples
    - Each sampling unit has a known and equal chance of selection
  20. 20What are the disadvantages of a simple random sample? (Yr 1, 1.2)- Not suitable when the population size or the sample size is large as it is potentially time consuming, disruptive and expensive
    - A sampling frame is needed
  21. 21What are the advantages of systematic sampling? (Yr 1, 1.2)- Simple and quick to use
    - Suitable for large samples and large populations
  22. 22What are the disadvantages of a systematic sample? (Yr 1, 1.2)- A sampling frame is needed
    - It can introduce bias if the sampling frame is not random
  23. 23What are the advantages of a stratified sample? (Yr 1, 1.2)- Sample accurately reflects the population structure
    - Guarantees proportional representation of groups within a population
  24. 24What are the disadvantages of a stratified sample? (Yr 1, 1.2)- Population must be clearly classified into distinct strata
    - Selection within each stratum suffers from the same disadvantages as simple random sampling
  25. 25What are the two types of non-random sampling? (Yr 1, 1.3)Quota sampling
    Opportunity sampling
  26. 26What is quota sampling? (Yr 1, 1.3)In quota sampling, an interviewer or researcher selects a sample that reflects the characteristics of the whole population
  27. 27How is quota sampling carried out? (Yr 1, 1.3)Population is divided into groups according to a given characteristic. The size of the group determines the proportion of the sample that should have that characteristic.
    Interviewer would meet people first and then allocate them to the appropriate quota
  28. 28What is opportunity sampling? (Yr 1, 1.3)Opportunity sampling consists of taking the sample from people who are available at the time the study is carried out and who fit the criteria you are looking for
  29. 29What are the advantages of quota sampling? (Yr 1. 1.3)- Allows a small sample to still be representative of the population
    - No sampling frame required
    - Quick, easy and inexpensive
    - Allows for easy comparison between different groups within a population
  30. 30What are the disadvantages of quota sampling? (Yr 1, 1.3)- Non-random sampling can introduce bias
    - Population must be divided into groups, which can be costly or inaccurate
    - Increasing scope of study increases number of groups, adds to time and expense
    - Non-responses aren't recorded as such
  31. 31What are the advantages of opportunity sampling? (Yr 1, 1.3)- Easy to carry out
    - Inexpensive
  32. 32What are the disadvantages of opportunity sampling? (Yr 1, 1.3)- Unlikely to provide a representative sample
    - Highly dependent on individual researcher
  33. 33What is quantitative data? Give an example (Yr 1, 1.4)Variable or data associated with numerical observations
    E.g you can give a number to shoe size so i shoe size is a quantitative variable
  34. 34What is qualitative data? Give an example (Yr 1, 1.4)Variables and data associated with non-numerical observations
    E.g you can't give a number to hair colour, therefore hair colour is a qualitative variable
  35. 35A variable that can take any value in a give range is called a .... (Yr 1, 1.4)...continuous variable
  36. 36A variable that can take only specific values in a given range is a... (Yr 1, 1.4)...discrete variable
  37. 37—

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Karteikarten am Statistics, erstellt von Charlotte Allen am 28/01/2019.
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Charlotte Allen
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