Statistics and Research in Psychology Essential Question: How do psychologists refer to the their research methodology, data and results?

I. Collection and Use of Data

A. Gathering the data When a psychologist does research, they are doing so for the purpose of collecting data Data is what the psychologist will look at to determine if their hypothesis was proven correct or incorrect (results may not be conclusive) If the psychologist wishes to try to formulate their data into a theory, then they must have great data

B. Now what do we do with the data? Unfortunately, collecting data is not enough The data must be organized in such a way that any other scientist can easily access the results of whatever research has been done This is where statistical awareness becomes important One must be able to show the connection between the data and the hypothesis One must also be able to prove that the data is valid and reliable

C. The Importance of Validity and Reliability All data that one wishes to use must be valid (preferably with a low SD) Invalidly collected data will cause a psychologist’s research findings to be called into question and possible not accepted All data must also be reliable If the data collected from any type of research cannot be repeated, then most psychologists will not accept the findings of a research study.

D. Organizing the Data Once the data is together, the researcher must be able to organize that data in a way that is easy to read and understand A good researcher will be mindful of this while they are gathering the data, so they should have charts, graphs, and other graphic organizers with them during the research Once everything is ready, psychologists must be able to create valid statistics based on their research

II. Data and Statistics

A. Descriptive Statistics These are statistics that describe data There are three main types of descriptive statistics that can used -Measures of Central Tendency -Measures of Variability -Correlational Coefficients

1. Measures of Central Tendency The main idea of M of CT is to figure out what is in the center of our research, or what is typical -Mode: The value that occurs most frequently in a study -Median: The halfway point in a set of data -Mean: What is the average in all of our scores

2. Measures of Variability The main idea of M of V is to figure out how far apart statistics are from each other -Range: The difference between the highest and lowest scores in a set of data -Standard Deviation: How far the scores in data are on average from the mean (High SD is when they are far from the mean on average. Low SD is when they not far from the mean on average) -High SD usually indicates validity

3. Correlation and Correlational Coefficients The main idea of correlation is to figure out how one variable relates to other variable when studied -Positive Correlation: Both variables increase/decrease together -Negative Correlation: The variables do not move in the same direction -Correlational Coefficients: Statistics that express the correlations between variables -Plus for positive, Minus for negative -Between and -1.00