psychology’s statistics module 03. module overview frequency distributions measures of central...

Psychology’s Statistics

Module 03

Module Overview

• Frequency Distributions

• Measures of Central Tendency

• Measures of Variation

• Normal Distribution

• Comparative Statistics

• Correlation Coefficient

• Statistical Inference

Click on the any of the above hyperlinks to go to that section in the presentation.

Psychology’s Statistics

Module 03: Psychology’s Statistics

Statistics

• Are a means to make data more meaningful

• Provide a method of organizing information so that it can be understood

Frequency Distributions


Sample Experiment

Frequency Distribution

• A list of scores placed in order from highest to lowest.

Bar Graphs

• Used to present data from frequency distributions

Measures of Central Tendency


Measures of Central Tendency

• Statistical methods for finding the center of a distribution

• Three methods:

– Mode

– Mean

– Median

Measures of Central Tendency:

Mode


Mode

• The most frequently occurring score or scores in a distribution.

• Most useful in circumstances where the data can be placed into distinct groups


Mean


Mean

• The arithmetic average of a distribution,

• obtained by adding the scores and then dividing by the number of scores.

• Usually the measure of central tendency of choice


Median


Median

• The middle score in a ranked distribution;

• half of the scores are above it,

• half are below it.

Median

Skewed

• Distorted; not evenly distributed around the mean.

Measures of Variation


Measures of Variation:Range


Range

• The difference between the highest and the lowest scores in a distribution.

Measures of Variation:Standard Deviation


Standard Deviation

• A computed measure of how much scores vary around the mean score of a distribution.

• The higher the standard deviation, the more the more spread out the scores are

Standard Deviation Calculation

• Calculate the mean of the data.

• Determine how far each score deviates from the average.

• Square the deviation scores and add them together.

• Take the square root of the average of the squared deviation scores.

Standard Deviation Calculation

Normal Distribution


Normal Distribution

• A frequency distribution that is shaped like a symmetrical bell.

• Most scores fall near the mean, with fewer and fewer scores at the extreme.

• The mean, median, and mode are all the same (the highest point of the curve) in a normal distribution.

Normal Distribution

Comparative Statistics


Percentage

• A comparative statistic that compares a score to a perfect score of 100 points.

Percentile Rank

• A comparative statistic that compares a score to other scores in an imaginary group of 100 individuals.

• The percentile rank indicates how many of the hundred scores are at or below a particular score.

Calculating Percentage Scores and Percentile Ranks

Correlation Coefficient


Correlation Coefficient

• A statistical measure of the strength of the relationship between two variables.

• Extent to which two things vary together

Positive Correlation

• As the value of one variable increases (or decreases), the value of the other variable increases (or decreases).

• A perfect positive correlation is +1.0.

• The closer the correlation is to +1.0 the stronger the relationship.

Negative Correlation

• As the value of one variable increases, the value of the other variable decreases.

• A perfect negative correlation if -1.0.

• The closer the correlation is to -1.0 the stronger the relationship.

Zero Correlation

• There is no relationship whatsoever between the two variables.

Zero Correlation

Statistical Inference


Inferential Statistics

• Statistics that can be used to make a decision or reach a conclusion about data.

Statistical Significance

• A statistical statement of how likely it is that a result occurred by chance alone.

Significance Difference

The End

Teacher Information• Types of Files

– This presentation has been saved as a “basic” Powerpoint file. While this file format placed a few limitations on the presentation, it insured the file would be compatible with the many versions of Powerpoint teachers use. To add functionality to the presentation, teachers may want to save the file for their specific version of Powerpoint.

• Animation– Once again, to insure compatibility with all versions of Powerpoint, none

of the slides are animated. To increase student interest, it is suggested teachers animate the slides wherever possible.

• Adding slides to this presentation– Teachers are encouraged to adapt this presentation to their personal

teaching style. To help keep a sense of continuity, blank slides which can be copied and pasted to a specific location in the presentation follow this “Teacher Information” section.

Teacher Information• Domain Coding

– Just as the textbook is organized around the APA National Standards, these Powerpoints are coded to those same standards. Included at the top of almost every slide is a small stripe, color coded to the APA National Standards.

• Scientific Inquiry Domain• Biopsychology Domain• Development and Learning Domain• Social Context Domain• Cognition Domain• Individual Variation Domain• Applications of Psychological Science Domain

• Key Terms and Definitions in Red– To emphasize their importance, all key terms from the text and their

definitions are printed in red. To maintain consistency, the definitions on the Powerpoint slides are identical to those in the textbook.

Teacher Information• Hyperlink Slides - Immediately after the unit title slide, a page (usually

slide #4 or #5) can be found listing all of the module’s subsections. While in slide show mode, clicking on any of these hyperlinks will take the user directly to the beginning of that subsection. This allows teachers quick access to each subsection.

• Continuity slides - Throughout this presentations there are slides, usually of graphics or tables, that build on one another. These are included for three purposes.

• By presenting information in small chunks, students will find it easier to process and remember the concepts.

• By continually changing slides, students will stay interested in the presentation.• To facilitate class discussion and critical thinking. Students should be encouraged to

think about “what might come next” in the series of slides.

• Please feel free to contact me at [email protected] with any questions, concerns, suggestions, etc. regarding these presentations.

Kent Korek

Germantown High School

Germantown, WI 53022

mailto:[email protected]

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psychology’s statistics module 03. module overview frequency distributions measures of central...

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