Assessment, Statistics, and Research

Independent Samples t- test Researchers use the independent samples t -test to find out if there is a significant difference between two sets of data. In the behavioral sciences, the data are often two sets of scores on tests or survey items. Significance can mean a lot of different things. In behavioral science, it is common to think of significance as a frequently occurring, and thus reliable, difference. Sometimes the language of statistics can be confusing. The independent sample t -test evaluates the differences between the arithmetic mean s of the two groups of scores, and assumes the scores are normally distributed . Usually, a difference needs to be at least large enough that a score difference as large, or larger than the one obtained, occurs only 5% of the time by chance. The calculations are usually done in spreadsheets like Excel or Google Sheets or in a program like SPSS . See the link below for a download about how to calculate a t-test. You wil

You can quickly reverse score survey items using widely available spreadsheets like Excel and Google Sheets or SPSS. For example, the freely available scale to measure Valor/ Bravery/ Courage has 10 items rated on a 1 – 5 scale. High scores represent more of the trait. But 4 items are worded as negative statements so, you have to reverse the item scores on the negative items to obtain a correct total score for courage. Sometimes test and survey creators refer to items as + or – keyed. Positive items are added together and the negative items must be reverse scored before adding to the total. Survey Items Example Following are the general directions for the 5-point rating from www.ipip.org Describe yourself as you generally are now, not as you wish to be in the future. Describe yourself as you honestly see yourself, in relation to other people you know of the same sex as you are, and roughly your same age. So that you can describe yourself in an honest ma

Lions of Kruger/ Geoff Sutton 2009 Courage is a virtue. Despite being an ancient virtue, courage is a relatively new topic of study in psychological science. As with any psychological concept, definitions can vary. Woodward and his colleagues have begun a line of inquiry, which includes a measurement scale. Here’s a 2007 definition: “Courage is the voluntary willingness to act, with or without varying levels of fear, in response to a threat to achieve an important, perhaps moral, outcome or goal. (p. 136)”      Read more about the psychology of courage. Factor analysis suggested participants identified three types of threats: Physical, social, and emotional. When scale items were analyzed, four factors emerged, which were categorized by the authors as follows: 1. work/employment courage 2. patriotic/religion/belief-based courage 3. social-moral courage 4. independent or family-based courage 23-item Measure A popular measure of courage is the