The thing that is manipulated in and experiment -- it can have more than one level

In this type of experimental design, each participant participates in each level of the IV

When participants in an experiment (particularly a repeated measures design) start to think they figure out what the experimenter wants and then change their behavior to fit

In this type of design, participants participate in every level of the IV; order effects can be a problem

The best way to overcome order effects in a repeated measures design

if we claim something is scientifically true, we must be able to specify what evidence it would take to prove it wrong

the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.

If a hypothesis predicts that students who consume caffeine prior to a test will score higher on the test. What kind of hypothesis is it?

If a hypothesis predicts that caffeine will have an effect on student performance, what type of hypothesis is it?

A clear statement that outlines what the researcher intends to investigate

Using exactly the same formalised procedures and instructions for all participants in a research study.

the clear description of a variable such that it can be accurately manipulated, measured or quantified, and the study can be replicated. This includes the way that the IV and DV in experiments, and the co-variables in correlations are described.

when a researcher repeats a study using exactly the same procedure and materials (you need good operational definitions for this!)

the group, sharing one or more characteristics, from which a sample is drawn

When a university student performing research selects other students to participate in the study because they are present at the university where the research is taking place

A random sample fairly represents the target population because:

If a sample is representative of the population, the results can be broadly applied to the population. This is known as

Participants are invited to participate, e.g. through advertisements via email or notices. Those who reply become the sample. One problem with this is that you don't get a variety of participants (not representative!)

In this type of sample, the researcher sorts the population into groups/categories, and then randomly selects from each group.