Year 10 Statistics

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Year 10 Statistics

• Module 1
• Sampling Collecting Data

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Statistics

• Sampling
• Why do we need to take a sample?
• Why do we not use the entire population ?
• Whats the purpose of a sample?

• Collecting Data
• Primary Data
• Data collected by yourself
• Secondary Data
• Data that has already been collected by other
  agencies

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Sampling

• Sampling Methods
• Stratified
• Quota
• Systematic
• Convenience
• Cluster

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Sampling Techniques

• Stratified
• a fixed percentage of the various groups
• GCSE Mathematics GCSE Statistics

• e.g. Find 10 of each Year group in a School
• Year 7 10 of 150 15
• Year 8 10 of 120 12
• Year 9 10 of 180 18
• Total Sample Size 45

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Sampling Techniques

• Quota
• a fixed number of people from the various groups
• GCSE Statistics

• e.g. Choose the same number of students from each
  Year group in a School
• Year 7 15 out of 150
• Year 8 15 out of 120
• Year 9 15 out of 180
• Total Sample Size 45

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Sampling Techniques

• Stratified Sample
• Year 7 10 of 150 15
• Year 8 10 of 120 12
• Year 9 10 of 180 18
• Total Sample Size 45

• Quota Sample
• Year 7 15 out of 150
• Year 8 15 out of 120
• Year 9 15 out of 180
• Total Sample Size 45

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Sampling Techniques

• Systematic
• Find a starting point and pick people at equal
  intervals
• GCSE Statistics

• Choose the position of the first person by a
  random method
• Choose after how many moves you will select
  subsequent people

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Sampling Techniques

• Cluster
• Choose several sub sections from a large sample
• GCSE Statistics

• Choose the sub-sections by a random method
• Choose the people from within these sub-sections
  by a random method

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Sampling Techniques

• Convenience
• Choose people as they pass by
• GCSE Statistics

• Choose a convenient position inside an
  establishment or in a shopping centre
• Choose people as they pass by - use a check list

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What is Randomness?

• It is NOT choosing your friends!
• It is one of the following methods-
• Rolling a die
• Names in a hat
• Generate random numbers

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Randomness?

• Does this mean closing your eyes and sticking a
  needle into a haystack
• or throwing a dart in the hope that you hit the
  target?

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Randomness

• Allocate all people a number
• Use of graphics calculator or list of random
  numbers
• State how the random numbers generated are used

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Further Guidelines

• www.speters.org.uk
• Click on
• Departments
• Mathematics
• Links
• Sampling Techniques

• www.speters.org.uk
• Click on
• Departments
• Mathematics
• Revision
• Syllabuses Level Descriptors
• Quicktests