statistics definitions Flashcards

(18 cards)

1
Q

raw data

A

data as it is first collected in a statistical investigation before it has been sorted or ordered

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2
Q

what is quantitative data

A

numerical data such as measures of height and weight

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3
Q

what is qualitative data

A

non-numerical data such as type of car or colour of hair

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4
Q

what is categorical data

A

variables that can be sorted into categories

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5
Q

what is continuous data

A

numerical data that can take values between two numbers like temperature

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6
Q

what is discrete data

A

numerical data that can only take one value like show size

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7
Q

what is ordinal data

A
position in a race or in a class test 
written in order of numerical value
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8
Q

what is bivariate data

A

pairs of related data values such as exam results and time spent on study

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9
Q

what is multivariate data

A

involves sets of three or more related data values like age, height and weight

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10
Q

what is primary data

A

data that you collect yourself

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11
Q

what is secondary data

A

data collected by a published source

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12
Q

what are the advantages and disadvantages of primary data

A

advantages:
- collection method known
- accuracy known
- questionnaire or survey can be designed properly to find answers to specific questions

disadvantages:
- collection of data can be expensive and time-consuming

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13
Q

what are the advantages and disadvantages of secondary data

A

advantages:

  • easy and cheap to obtain
  • data from known organisations is usually reliable like the UK office for National Statistics

disadvantages:

  • data source may not be reliable
  • data might contain errors
  • data might not be suitable to find answers to specific questions
  • collection method unknown
  • data might be out of date
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14
Q

what needs to be controlled when collecting data

A
  • extraneous variables which are any variables that the researcher is not interested in but could affect the results of the experiment
  • explanatory data which is like the control variable in science
  • response variable which is like the dependent variable in science
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15
Q

what are field experiments

A

carried out in an everyday (uncontrolled) environment but the researcher sets up the situation and variables are controlled

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16
Q

what is a natural experiment

A

carried out in an everyday (uncontrolled) environment but the researcher has no control over any variables

17
Q

how must you clean data

A
  • identify and correct or remove inaccurate data values or extreme values
  • check units are consistent
  • record values without units or with other symbols
  • decide what to do about missing data
18
Q

why must you check and clean data

A
  • to ensure it is consistent and accurate before you process it otherwise you results may be invalid
  • collected data may contain outliers or anomalous values that do not fit the pattern of the rest of the data and may skew your results
  • outliers can be ignored if they are due to measuring or recording errors
  • you need to check that your collection plan hasn’t affected the reliability of your results