AP Psychology Module 7&8 Vocab

standard deviation

Definition: a computed measure of how much scores vary around the mean score Application: Standard deviation tells you how tightly your data is clustered around the mean. When the bell curve is flattened (your data is spread out), you have a large standard deviation — your data is further away from the mean. When the bell curve is very steep, your data has a small standard deviation — your data is tightly clustered around the mean.

skewed distribution

Definition: a representation of scores that lack symmetry around their average value. Application: If one tail is longer than another, the distribution is skewed. These distributions are sometimes called asymmetric or asymmetrical distributions as they don't show any kind of symmetry. Symmetry means that one half of the distribution is a mirror image of the other half.

statistical significance

Definition: a statistical statement of how likely it is that an obtained result occurred by chance Application: When researchers say the findings of a study were "statistically significant," they do not necessarily mean the findings are important. Statistical significance refers to whether any differences observed between groups being studied are "real" or whether they are simply due to chance.

normal curve

Definition: a symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean (about 68 percent fall within one standard deviation of it) and fewer and fewer near the extremes Application: The area under the normal curve is equal to 1.0. Normal distributions are denser in the center and less dense in the tails. Normal distributions are defined by two parameters, the mean and the standard deviation. 68% of the area of a normal distribution is within one standard deviation of the mean.

informed consent

Definition: an ethical principle that research participants be told enough to enable them to choose whether they want to participate Application: Informed consent means the knowing consent of an individual without undue inducement or any element of force, fraud, duress or any other form of constraint or coercion. Sufficient information must be presented (in understandable language) so that the potential subject can make an informed judgment about participation.

histogram

Definition: bar grams depicting a frequency distribution Application: To interpret a histogram, we find the events on the x-axis and the counts on the y-axis. Each event has a rectangle that shows what its count (or frequency) is.

Inferential Statistics

Definition: numerical data that allows one to generalize- to infer from sample data the probability of something being true of a population Application: For instance, we use 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.

descriptive statistics

Definition: numerical data used to measure and describe characteristics of groups. Includes measures of central tendency and measures of variation Application: For example, it would not be useful to know that all of the participants in our example wore blue shoes. However, it would be useful to know how spread out their anxiety ratings were. Descriptive statistics is at the heart of all quantitative analysis.

mean

Definition: the arithmetic average (the total sum of all of the scores divided by the number of scores) Application: The mean (or average) is the most popular and well known measure of central tendency. It can be used with both discrete and continuous data, although its use is most often with continuous data.

culture

Definition: the enduring behaviors, ideas, attitudes, values, and traditions shared by a group of people and transmitted from one generation to the next Application: These ideas, behaviors, traditions, etc. are passed on from one generation to the next and are typically resistant to change over time. Cultures vary widely not only across the world, but even right next door. For example, if you live in America and then visit different areas of Europe, you may notice that people often get closer to each other physically in social settings - tables are often closer together at restaurants, people stand closer to each other when they speak, etc.

range

Definition: the gap between the lowest and highest scores Application: The range of a set of data is the difference between the greatest and least data values. The range gives you a measure of the spread of the data.

median

Definition: the middle score in a distribution; half the scores are above it and half are below it Application: The median is the middle score for a set of data that has been arranged in order of magnitude. The median is less affected by outliers and skewed data.

mode

Definition: the most frequently occurring score or scores Application: On a histogram it represents the highest bar in a bar chart or histogram. You can, therefore, sometimes consider the mode as being the most popular option.

debriefing

Definition: the postexperimental explanation of a study, including its purpose and any deceptions, to its participants Application: Psychological studies with human participants include a debriefing discussion between the researcher and the participant after the experiment is over. These conversations can be structured or semi-structured and are a critical part of any experiment or psychological study that involves human participants.