IB Internal Assessment Section B: Methods of Investigation
Requirements • Students must describe the method(s) used to collect information. (questionnaires, interviews, annotated photographs, etc) • The description must identify the sampling technique used (random, systematic, or stratified) and how it will be used. • The method(s) used must be justified and must enable a sufficient quality and quantity of primary data to be produced to allow the fieldwork question to be investigated. • The suggested length of this section for work appropriate to criterion B is approximately 300 words.
Focus for Section B: Describe the Methods Used to Collect Data • Questionnaires (types of questions, how many questionnaires, etc) • Interviews (with who, why? )
Sampling Techniques • • Found in Fieldwork Guide Random Systematic Stratified • Must be discussed and decided by entire group. Cannot be an individual decision. • If 2 group members use one method and 2 others use another, your data is flawed!
What is sampling? • A short-cut method for investigating a whole population • Data is gathered from a small part of the whole population and used to inform what the whole picture is like
Why Sample? • In reality there is simply not enough time, energy, money, labor/manpower, equipment or access to suitable sites to measure every single item or site within the population. • Therefore researchers adopt an appropriate sampling strategy to obtain a representative and statistically valid sample of the whole.
Random Sampling • What is it? • Least biased of all sampling techniques: there is no subjectivity - each member of the total population has an equal chance of selection. • Grid System and Random Point: Demonstrate on board
Random Sampling • Strengths – Useful in large populations – Avoids bias • Limitations – Can lead to poor representation of general population if general areas are underrepresented – What if 75 of your 100 numbers are in Hegewisch?
Systematic Sampling • What is it? • Choose samples through a systematic or uniform method. – evenly distributed across a spatial context, e. g. every ½ mile – at regular intervals across a temporal context, e. g. every 10 minutes of walking • regularly numbered, every 6 th house on the north side of the street
Systematic Sampling • Strengths – More straight-forward than random sampling. – Don’t necessarily have to use a grid … sampling just has to be at uniform intervals. – More easily achieves good coverage of study area than random sampling. • Limitations – More biased since not all units have an equal chance of selection.
Stratified Sampling • What is it? • Used when population made up of sub-sets of known size and that comprise different proportions of total population. • Stratified sampling ensures results are proportional and representative of the whole. • Example, if you know that 75% of population is Hispanic, they should represent 75% of questionnaires • Or dividing into 3 or 4 equal groups based on neighborhood. • Stratified Sampling may be combined with both Systematic and Random: Stratified Systematic Sampling and Stratified Random Sampling
Stratified Sampling • Strengths – Can use with random or systematic sampling – With known proportions of sub-sets, can generate results which are more representative of the whole population. – Can make correlations and comparisons between subsets. • Limitations – To work properly, the proportions of the sub-sets must be known and accurate. – It can be hard to stratify questionnaire data collection - accurate, up to date population data may not be available and it may be hard to identify people's age or social background effectively.
Justification of Methods • The method(s) used must be justified and must enable a sufficient quality and quantity of primary data to be produced to allow the fieldwork question to be investigated. • Justify why you ask the questions you do, interview the people you interview, sample using the method you choose. • You can justify questionnaire questions as well.
Section B Sample Close Read • Take some time to read Jenny Nevarez’s Section B. • Highlight/label the following: • Description of methods • Sampling method description • Justification of methods (see what she does with copy of questionnaire)
Скачать презентацию IB Internal Assessment Section B Methods of Investigation
b67e3a894139eda8e26f98edbe7b664e.ppt