| Hypothesis |
A precise, testable statement or prediction about the expected outcome of an investigation. |
| Null hypothesis prediction |
One that states results are due to chance and are not significant in terms of supporting the idea being investigated. |
| Research hypothesis prediction |
One that states that results are not due to chance and that they are significant in terms of supporting the idea being investigated. |
| One-tailed hypothesis |
A directional hypothesis. |
| Two-tailed hypothesis |
One in which the direction of results is not predicted. |
| Random sampling |
Everyone in the entire target population has an equal chance of being selected. |
| Opportunity sampling |
Uses people from target population available at the time. |
| Systematic sampling |
Chooses subjects in a systematic way. |
| Self-selected sample |
Participants volunteer. |
| Stratified sampling |
Divides target population into groups, people in sample from each group in same proportions as population. |
| Counterbalancing |
Alternating the order in which participants perform in different conditions of an experiment. |
| Randomisation |
Material for each condition in an experiment is presented in a random order, this is also to prevent order effects. |
| Single-blind design |
Participants do not know which condition (experimental or control) they are in. |
| Double-blind design |
Neither the participants nor the experimenter know which condition people are being treated to. |
| Time sampling |
Observations may be made at regular time intervals and coded. |
| Event sampling |
Keep a tally chart of each time a type of behaviour occurs. |
| Point sampling |
Focus on one individual at a time for set period of time. |
| Quantitative research |
Gathers data in numerical form and is concerned with making 'scientific' measurements. Quantitative data analysis uses a barrage of inferential statistical tests. |
| Qualitative research |
Gathers information that is not in numerical form. |
| Arithmetic mean |
All values in a set of data are added together and divided by the number of values (N). |
| Median |
All values are arranged in order, the middle value is the median. |
| Mode |
The most frequent value or score in a set of data. |
| Range |
Simple measure of dispersion- shows the total spread of data. |