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Flashcards

1. Statistical Sampling

Camilla Gentry Maths A level English 52 cards

Cards in this deck (52)

  1. 1Define 'population'The whole set of items that are of interest
  2. 2Define 'sample'A selection of observations taken from a subset of the population which is used to find out information about the population as a whole
  3. 3What is the purpose of a census?To observe or measure every member of a population
  4. 4What is an advantage of a census?It should give a completely accurate result as all members of the population are observed.
  5. 5What are the disadvantages (3) of a census?1. Time consuming and expensive
    2. Cannot be used when the testing process destroys the item
    3. Hard to process large quantity of data
  6. 6What are the advantages (3) of samples?1. Less time consuming and expensive than a census
    2. Fewer people have to respond
    3. Less data to process
  7. 7What are the disadvantages (2) of samples?1. Data may not be as accurate
    2. Sample may not be large enough to give information about small sub-groups of the population
  8. 8What are individual units of a population called?Sampling units
  9. 9What is a sampling frame?A list of the items or people forming a population from which a sample is taken
  10. 10Name the three methods of random samplingSimple random sampling
    Systematic sampling
    Stratified sampling
  11. 11What is the primary advantage of random sampling in general?Every member of the population has an equal chance of being selected which means the sample should be representative of the population. It also helps remove bias from a sample.
  12. 12Define 'simple random sample'Where every sample of size n has an equal chance of being selected
  13. 13How is a simple random sample usually carried out?A sampling frame (e.g. list of people) is taken and each member is given a unique number. A selection of numbers is then chosen at random.
  14. 14What are the two methods of choosing the random numbers for simple random sampling?Random number generation
    Lottery sampling
  15. 15What is lottery sampling?A method through which random members of a population are chosen. Each member is written on tickets and placed in a 'hat'. The required number of tickets would then be drawn out.
  16. 16Define 'systematic sampling'Where the required elements are chosen at regular intervals from an ordered list
  17. 17Describe how systematic sampling is typically carried outThe first member should be chosen at random and then members should be selected at the decided intervals
  18. 18Define 'stratified sampling'The population is divided into mutually exclusive strata (e.g. male/female) and a random sample is taken from each
  19. 19What are the advantages (3) of simple random sampling?1. Free of bias
    2. Easy and cheap to implement for small populations and samples
    3. Each sampling unit has a known and equal chance of selection
  20. 20What are the disadvantages (2) of simple random sampling?1. Not suitable when the population or sample size is large
    2. Sampling frame is needed
  21. 21What are the advantages (2) of systematic sampling?1. Simple, quick to use
    2. Suitable for large samples and populations
  22. 22What are the disadvantages (2) of systematic sampling?1. Sampling frame needed
    2. Can introduce bias if sampling frame is not random
  23. 23What are the advantages (2) of stratified sampling?1. Sample accurately reflects the population structure
    2. Guarantees proportional representation of groups within a population
  24. 24What are the disadvantages (2) of stratified sampling?1. Population must be clearly classified into distinct strata
    2. Selection within stratum not suitable when population or sample is large and a sampling frame is needed
  25. 25Name the two types of non-random samplingQuota sampling
    Opportunity sampling
  26. 26Define 'quota sampling'An interviewer or researcher selects a sample that reflects the characteristics of the whole population
  27. 27How is quota sampling usually carried out?The population is divided into groups according to a given characteristic and the size of each group determines the proportion of the sample that should have that characteristic. People are assessed and allocated into the appropriate quota. Anyone who refuses to be interviewed or the quota they fit in is full, they are ignored and the next person is then interviewed.
  28. 28Define 'opportunity sampling'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 is opportunity sampling sometimes called?Convenience sampling
  30. 30What are the advantages (4) of quota sampling?1. Allows a small sample to still be representative of a population
    2. No sampling frame needed
    3. Quick, easy, inexpensive
    4. Allows for easy comparison between different groups of a population
  31. 31What are the disadvantages (4) of quota sampling?1. Non-random sampling can introduce bias
    2. Population has to be divided into groups (can be costly or inaccurate)
    3. Increasing scope of study increases number of groups (adds time and expense)
    4. Non-responses not recorded
  32. 32What are the advantages (2) of opportunity sampling?1. Easy to carry out
    2. Inexpensive
  33. 33What are the disadvantages (2) of opportunity sampling?1. Unlikely to provide a representative sample
    2. Highly dependent on individual researcher
  34. 34Define 'quantitative variables/data'Variables or data associated with numerical observations
  35. 35Define 'qualitative variables/data'Variables or data associated with non-numerical observations
  36. 36Define 'continuous variable'A variable that can take any value in a given range
  37. 37Define 'discrete variable'A variable that can take only specific values in a given range
  38. 38Name the five UK weather stations from the large data setLeuchars
    Leeming
    Heathrow
    Hurn
    Camborne
  39. 39Name the three overseas weather stations from the large data setJacksonville
    Beijing
    Perth
  40. 40What is daily mean temperature and what are the units used for it?The average of the hourly temperature readings during a 24-hour period
    °C
  41. 41What is the unit used for daily total rainfall?mm (millimetres)
  42. 42What is daily total sunshine recorded to?The nearest tenth of an hour
  43. 43What is the unit used for daily mean wind speed?Knots
  44. 44How are mean wind speed directions given?As bearings and cardinal (compass) directions
  45. 45What is the name of the scale used to categorise data for mean wind speed?Beaufort scale
  46. 46What is daily maximum gust and what unit is used to measure it?The highest instantaneous windspeed recorded
    Knots
  47. 47How is daily maximum relative humidity given?As a percentage of air saturations with water vapour
  48. 48How is daily mean cloud cover measured?In 'oktas' (eights of the sky covered by clouds)
  49. 49What is daily mean visibility measure in?Decametres (Dm)
  50. 50What is daily mean visibility?The greatest horizontal distance at which an object can be seen in daylight
  51. 51What is daily mean pressure measured in?Hectopascals (hPa)
  52. 52For daily total rainfall, what are amounts less than 0.05 mm recorded as?Trace ('tr')

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Description
Edexcel Mathematics A Level Paper 2: Statistics and Mechanics
Created by
Camilla Gentry
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  • Created by Riya X · Apr 24, 2018
  • Copied by Camilla Gentry · Feb 21, 2019
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