Statistical Principles In Paychological Research

Procedures for assessing whether the results obtained with a sample are likely to reflect characteristics of the population as a whole

Numbers that describe the data from a study in a way that summarises their essential features

A method of organising the data to show how frequently participants received each of the many possible scores

Plots ranges of scores along the x axis and the frequency of scores in each range along the y axis

Measures which provide an index of the way a typical participant responded

Average of the scores of all participants, found by dividing the total of all scores by the number of participants

The most common score

The score that falls in the middle of the distribution

The amount the average participant deviates from the mean of the sample

The scores of most participants fall in the middle of a bell-shaped distribution, and progressively fewer participants have scores at either extreme

The percentage of scores that fall below a score

The extent to which participants tend to differ from one another

The likelihood that results of a study have occurred simply by chance

Represents the probability that any positive findings obtained with the sample (such as differences between two experimental conditions) were just a matter of chance

A measure of the magnitude of an experimental effect or the strength of a relationship

Compares the observed data with the results that would be expected by chance and tests the likelihood that the differences between observed and expected are accidental. This test is used if both DV and IV are categorical

A statistical procedure used to compare the means of two or more groups

A test of statistical significance used when comparing the mean scores of two groups