random tings

randoms tings

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  • Created on: 02-06-11 18:35

Section 2 - Experiments

Lab experiment: A;can lead to cause and effect being established. D;demand characteristics

 Field experiment: A;greater ecological validity as it is done in the ppt natural environment. D;difficult to control variables

Natural experiment: A;greater ecological validty than both above as it occurs naturally. D;difficult to control variables

Questionnaire: A;easy to replicate once written. D;does not gather in depth info if questions are close ended.

Interview: A; flexible and sensitive to the ppt responses D;more time consuming to carry out therefor no good for groups

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Section 2 - Experiments

Observational study: A; Behaviour is naturally occuring therefor has high ecological validity. D; extraneous variables difficult to control.

Corelational study: A;provide valuable info on strength of a relationship between two variables. D;unknown vairable maybe influencing correlation.

Case study: A;generates good in depth qualitative data providing reasons for things. D;cases usually unique so reliability cannot be assesed by replication.

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Section 2 - Reliability

Extent to which the study is consistent/weather the same findings can be found

Test-retest reliability: Where the test is carried out on two seperate occasions and results are compared

Split half method: Half of the questions correlated to the other half of questions and high corrrelation means high reliability

Inter rater reliability: consistency of observers/when 2 or more people are observing the same thing and if correlation is high Observer reliability is acheived.

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Section 2 - Validity

The extent to which something measures what it claims too

Experimental: is the manipulation of one variable really causing a change in another

Ecological: Can the findings or effects observed be generalised from the experiment to real life

Content: to ensure the content of the experiment is a representation of the area

Concurrent: Assess a new test with an old one which has already deemed to be valid and if they perform simular the new test is valid

Construct: weather what it is measuring matches an underlying construct

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Section 2 - Sampling

Random: A;Produces unbiased sample as there is no personal selection. D;Is time consuming as the process takes time.

Self selecting: A;quick and easy to gain a sample this way. D; Ppt has special characteristics as they have been able to volunteer.

Systematic: A;Easy once the sampling frame has been gained. D;Every person does not stand an equal chance of being picked.

Opportunity: A;Quick and easy as the researcher uses the first person they find. D;Technique produces very biased sample as they have been directly chosen by the researcher.

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Section 2 - Sampling

Stratified: A;Sample is gained in proportion to the population so is representative. D;Proportions must be already known in order to be calculated e,g; gender balance race balance etc.

Quota: A;Sample gained is in proportion to the population. D;Proportions must be already known in order to be calculated e,g; gender balance race balance etc.

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Section 2 - Ethics

Consent: ppt should be fully informed about the experiment in order to make an informed decision therefor does not occur where it needs to be secret.

Deception: Missinformed about experiment.

Withdrawl: Ppt should be told they have the right to withdrawl from the investigation

Confidentiality: Information should be kept between the ppt and researcher

Protection: ppt should be protected from physical or physiological damage/harm.

Debreifing: At the end of the study information should be past on about the study such as finding results any information that was left out throughtout the investigation.

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Section 2 - Averages

Mode: A;Not influenced by extreme results. D;Not useful if there are many equal modes.

Median: A;Not distorted by extreme values D;Less sensitive measure of central tendancy.

Mean: A;Most sensitive measure of central tendancy as it sits at the center of all deviations. D;can be distorted by extreme variables.

Range: A;Quick and easy to calculate. D;distorted by extreme variables

Bar Charts: A; Allows visual display of nominal level data. D;Can only be used with discrete data.

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Section 2 - Averages

Histograms: A;Allows visual display of interval/ratio data. D;More difficult to compare two data sets.

Scatter graphs: A;Demonstrates range and outliers as best fit can be drawn. D;No cause and effects can be determined between the 2 variables.


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