Statistics Chapter 1: Collecting Data
- Created by: 11APhillips
- Created on: 05-12-15 20:53
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- Statistics Chapter 1: Collecting Data
- Census v Sample
- Sample = Part of Population
- Two Types
- Random
- Simple Random
- Stratified (number in strata/total*sample size)
- Random number generator
- Non Random
- Quota Sampling - Se number (20 teenage boys etc)
- Cluster - Data Split into clusters, pick one randomly
- Systematic - Number in sample/total=collect every....values from random starting point
- Random
- Sampling Frame = List of all people/items in Sample
- Sampling Unit = All people/items in sample
- Two Types
- Census=Whole Population
- Census Ads: Unbiased/Accurate/Fully Representative
- Disads: Difficult to use whole population/expensive/time consuming
- Sample Ads: Less time consuming/Cheap/no need to collect lots of data
- Disads: May Be biased/unrepresentative
- Sample = Part of Population
- Primary v Secondary Data
- Primary Ads: Accuracy known/know how obtained
- Primary Disads: Time consuming/Expensive
- Secondary Ads: Easy/cheap to obtain
- Disads: May be out of data/May contain Mistakes/Method of collection unknown
- Primary Ads: Accuracy known/know how obtained
- Capture Recapture
- N=(Mn)/(m)
- Assumptions: No births or deaths/No migration (same subjects)/marking doesn't affect
- Pilot Surveys/Control Groups
- Pilot Survey: Small version of sample to see if qs are right and see results
- Control Group: Used in Drug Trials placebo/two groups etc
- Questionnaires
- Closed Question: Specific Answers but may not cover all
- Open Questions: Any answer but may not get answer needed
- Leading Questions = Bad
- Quantitative/Qualitative
- Continuous/Discrete
- Categorical - Sorted into non overlapping categories
- Ranked - Can be put in order
- Bivariate - Pairs of related variables
- Ranked - Can be put in order
- Categorical - Sorted into non overlapping categories
- Continuous/Discrete
- Census v Sample
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