Psychology research methods

• null hypothesis


  the hypothesis that there is no significant difference between two or more sets of data
• alternative hypothesis


  The hypothesis that states there is a difference between two or more sets of data.
• directional (one tail) hypothesis


  A directional hypothesis is when someone makes a specific prediction about an effect or relationship between two variables.
• non-directional (two tailed) hypothesis

  A non-directional hypothesis does not specify the type of change or relationship that is expected to occur.
• Nominal Data


  data of categories only. Data cannot be arranged in an ordering scheme. (Gender, Race, Religion)
• ordinal data


  data exists in categories that are ordered but differences cannot be determined or they are meaningless. (Example: 1st, 2nd, 3rd)
• interval data and ratio data


  a scale with edqual intervals are used e.g mins, kg, number of words recalled in a memory test or percentage score in an exam. Ratio data is on a scale, but has a true zero e.g weight, height, time, distance.
• repeated measures design


  The same participants are used in all the conditions in an experiment.
• Independent measures design


  Where each participant is only assigned to one condition of the IV.
• matched pairs design


  Participants are matched on key characteristics. One participant does control condition and the other does the experimental condition.
• dependent variable


  The measurable effect, outcome, or response in which the research is interested.
• independent variable


  The experimental factor that is manipulated; the variable whose effect is being studied.
• Labatory experiment


  An experiment that takes place in a controlled environment. Researcher has full control of IV an DV, and can control EVs.
• field experiment


  an experiment conducted in the participants' natural environment
• quasi experiment


  An experiment in which investigators make use of control and experimental groups that already exist.
• structured observation


  researcher identifies beforehand which behaviors are to be observed and recorded
• unstructured observation


  a great deal of flexibility is allowed in terms of what the observers note and record
• naturalistic observation


  a descriptive technique of observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation
• Controlled observation


  A form of investigation in which behaviour is observed but under controlled conditions.
• participant observation


  a naturalistic observation in which the observer becomes a participant in the group being observed
• Non-participant observation


  when the researcher observes behavior without participating in that behavior
• overt observation


  Participants know they are being observed
• covert observation


  Participants do not know they are being observed
• questionnaire


  a written set of questions to be answered by a research participant
• structured interview


  A selection interview that consists of a predetermined set of questions for the interviewer to ask
• semi-structured interview


  There is a list of questions that have been worked out in advance but interviewers are also free to ask follow up questions when they feel it is appropriate.
• unstructured interview


  An interview in which the question-answer sequence is spontaneous, open-ended, and flexible.
• Obtaining data for correlational analysis


  When researchers correlate two sets of data that already exist and looking at 'an association that is found between two variables'. There is no IV or DV, just co-variables.
• positive correlation


  a relationship between two variables in which both variables either increase or decrease together
• negative correlation


  as one variable increases, the other decreases
• no correlation


  There is no relationship between data sets.
• Research aim


  General purpose of the study
• research question


  A question that can be answered by an experiment or series of experiments
• target population and sample


  The group of people the researcher is interested in and from which the sample is drawn
• random sampling


  a method of sampling that gives each person in a group the same chance of being selected
• snowball sampling


  participants are asked to recommend acquaintances for the study
• Opportunity sampling


  a sample of whoever happens to be there and agrees to participate
• self-selected sampling


  A sampling method made up of volunteers
• extraneous variable


  In an experiment, a variable other than the IV that might cause unwanted changes in the DV.
• coding frames


  a list of behavioral categories a researcher is attempting to record