Statistical Methods in Psychology

Descriptive Statistics

Organize and summarize data, statistical procedures that organize and summarize research data

Inferential Statistics

Makes a generalization and takes information from a smaller group to a larger group

Descriptive Statistics

Organize and summarize data, statistical procedures that organize and summarize research data

Inferential Statistics

Makes a generalization and takes information from a smaller group to a larger group

Probability

There is nothing that is 100 percent guaranteed , likelihood that a particular event will occur

Variable

This is something that can be manipulated, it is something that changes

Constant

a number representing a quantity assumed to have a fixed value in a specified mathematical context

Independent Variable

(statistics) a variable whose values are independent of changes in the values of other variables

Dependent Variable

(statistics) a variable in a logical or mathematical expression whose value depends in the independent variable

Sample

What or who you are testing

Continuous

There is an infinite amount of numbers between two given points

Discrete

There are finite numbers of numbers between any two data points

Nominal

Pertains to sets of categories in which objects are classified

Ordinal

Indicates in what order the groups should appear

interval

Determines the distance between scales and allows comparison to other units

ratio

describes equal distances between scale units

mean

is the average calculated by adding all the data points together and dividing the numbers by the given numbers. this is efficient with no outliers

median

is the number that is in the middle put them in order. Gives an accurate summary of data set

mode

is the most uncommon, it is the number that appears the most (it is useless if there is no repetition)

Standard Deviation

a measure of variability that describes an average distance of every score from the mean

Variance

The measure of the general dispersion of data in a sample. shows how far data points are from one another

z score

in a normal distribution it tells you how far a number is above or below mean in terms of standard deviations.

Central Tendency

a number that describes something about the "average" score of a distribution

Sampling Distribution

a distribution of statistics obtained by selecting all the possible samples of a specific size from a population

Null Hypothesis

The hypothesis that states there is no difference between two or more sets of data.

Alternative Hypothesis

Hypothesis that states that results are not due to chance and that they are significant in terms of supporting the idea being investigated.

One-Sample T-Test

An inferential statistical procedure that uses the mean for one sample of data for either estimating the mean of the population or testing whether the mean of the population equals some claimed value.

Independent Samples t test

the statistical procedure that is appropriate when the scores meet the requirements of a parametric test, the research design involves a between subject design, and there're two conditions of the independent variable

Hypothesis testing

A procedure, based on sample evidence and probability theory, used to determine whether the hypothesis is a reasonable statement and should not be rejected or is unreasonable and should be rejected.

Type I Error

Error of rejecting null hypothesis when in fact it is true (also called a "false positive"). You think you found a cause effect relationship but ONE IS NOT THERE

Type II Error

error of failing to reject a null hypothesis when in fact it is false (also called a "false negative"). You think there is NO CAUSE EFFECT but THERE IS

Alpha Inflation

the fact that our probability to commit a Type 1 error increases as the number of tests increases.

One Way Anova

An Analysis of Variance used when there is only one main effect.

Factorial Anova

An Analysis of Variance used when there are two or more independent variables. When there are two, the ANOVA is called a Two-Way ANOVA, three independent variables would use a Three-Way ANOVA, etc.