Psy 113 chapter 1

Internal/External Validity

A distinction can be made between internal and external validity. These types of validity are relevant to evaluating the validity of a research study / procedure. Internal validity refers to whether the effects observed in a study are due to the manipulation of the independent variable and not some other factor.

Strong vs. weak correlation coefficients

Here r = +1.0 describes a perfect positive correlation and r = -1.0 describes a perfect negative correlation. The closer the coefficients are to +1.0 and -1.0, the greater the strength of the relationship between the variables.

Positive vs. negative vs. no correlation

In a negative correlation, the variables move in inverse, or opposite, directions. In other words, as one variable increases, the other variable decreases. ... When two variables have a positive correlation, it means the variables move in the same direction. This means that as one variable increases, so does the other one.

Correlation Coefficient

Pearson's r, a measure of the strength and direction of the linear relationship between two variables that is defined as the (sample) covariance of the variables divided by the product of their (sample) standard deviations.

APA ethical guidelines

The American Psychological Association's (APA) Ethical Principles of Psychologists and Code of Conduct (hereinafter referred to as the Ethics Code) consists of an Introduction, a Preamble, five General Principles (A-E) and specific Ethical Standards. ... The Ethical Standards are not exhaustive.

Control Group

The control group is defined as the group in an experiment or study that does not receive treatment by the researchers and is then used as a benchmark to measure how the other tested subjects do.

Independent vs. dependent variables

The two main variables in an experiment are the independent and dependent variable. An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable. A dependent variable is the variable being tested and measured in a scientific experiment.

Calculating the mean, median, & model

To find the median, your numbers have to be listed in numerical order from smallest to largest, so you may have to rewrite your list before you can find the median. The "mode" is the value that occurs most often. If no number in the list is repeated, then there is no mode for the list.

Standard Deviation

a quantity calculated to indicate the extent of deviation for a group as a whole.

standard deviation

a quantity calculated to indicate the extent of deviation for a group as a whole.

hypothesis

a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

Descriptive Statistics

are used to describe the basic features of the data in a study. They provide simple summaries about the sample and the measures. Together with simple graphics analysis, they form the basis of virtually every quantitative analysis of data.

Confounding variables

are variables that the researcher failed to control, or eliminate, damaging the internal validity of an experiment.

Naturalistic observation

is a research method commonly used by psychologists and other social scientists. This technique involves observing subjects in their natural environment.

Case studies

is an in depth study of a particular situation rather than a sweeping statistical survey. It is a method used to narrow down a very broad field of research into one easily researchable topic.

Experimental Group

is the group on which the experimental procedure is performed. The independent variable is changed for the group and the response or change in the dependent variable is recorded. In contrast, the group that does not receive the treatment or in which the independent variable is held constant is called the control group.

Experimentation

the process of performing a scientific procedure, especially in a laboratory, to determine something.

Inferential Statistics

to try to infer from the sample data what the population might think. Or, we use inferential statistics to make judgments of the probability that an observed difference between groups is a dependable one or one that might have happened by chance in this study.