"The set of all individuals of interest in a particular study."
ex. Juniors in college, pregnant women, college graduates, children that go to a specific preschool.
"A set of individuals selected from a population, usually intended to represent the population in a research study."
ex. 500 undergrads out of the entire college campus, where 'college campus' is the Population.
"A characteristic or condition that changes or has different values for different individuals."
ex. Peoples height, their moods, their gender. The time of day, the type of weather.
"Measurements of Observations." aka Measuring the variables, or, The Variables.
"Data set - A collection of measurements or observations.
Datum - A single measurement or observation, also known as a Score."
"A value, usually a numerical value, that describes a population. A parameter is usually derived from measurements of the individuals in the population."
ex. Average IQ of the population, number of fish the population caught.
"A value, usually a numerical value, that describes a sample. A statistic is usually derived from measurements of the individuals in the sample."
ex. Average age of the sample, number of fish the sample caught.
"Statistical procedures used to summarize, organize, and simplify data.
ex. A way to view the data more easily. Such as using tables or graphs, or summarizing all the data into averages.
"Techniques that allow us to study samples and then make generalizations about the populations from which they were selected."
ex. Using samples to make observations about a population.
"The discrepancy, or amount of error, that exists between a sample statistic and the corresponding population parameter."
ex. Maybe the sample has taller people on average than the rest of the population, so there's a discrepancy in data.
"Two different variables are observed to determine whether there is a relationship between them."
ex. Can show a relation between two variables, but cannot show a cause. Does not show cause and effect, only a relationship of some sort.
"One variable is manipulated while another variable is observed and measured. To establish a cause-and-effect relationship between the two variables, n experiment attempts to control all other variables to prevent them from influencing the results."
"The variable that is manipulated by the researcher." Also, the variables that were manipulated before the experiment in order to make those variables consistent.
ex. So the amount of caffeine given to school children would be the independent variable.
The Dependent Variable
"The one that is observed to assess the effect of the treatment."
ex. A scale of how active the children were after receiving the caffeine treatment.
"Where individuals do not receive the experimental treatment. Instead they either get nothing of a placebo. This provides a baseline for comparisons."
ex. Another group of children aren't given any caffeine at all, and their activity level is scored.
These are the ones that do receive the treatment.
"In a non experimental study, the 'independent variable' that is used to create the different groups of scores is often called this."
Experimental Study - Independent Variable
Non experimental study - Quasi-independent Variable
"Internal attributes or characteristics that cannot be directly observed but are useful for describing and explaining behavior."
ex. Attributes and characteristics such as anxiety, personal resolve, moral strength, anger, etc.
These are definitions given to constructs using external behaviors as a way to measure the extent of the internal attribute/characteristic.
ex. Restless sleep could be matched up with anxiety, physical violence could be matched up with anger.
"This consists of separate, indivisible categories. No values can exist between two neighboring categories."
ex. There is 1, and there is 2. There cannot be half, or 3/5's. There is an elephant, and there is a frog, there is no frogephant.
"There are an infinite number of possible values that fall between any two observed values. It can be divisible into an infinite number of fractional parts."
ex. Distance from one place to another, 3 feet, 1 foot, 1/2 foot, 1 inch, 1/2 inch, etc.
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