Problems with Correlational Research Directionality Problem A problem

# Problems with correlational research directionality

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Problems with Correlational Research
Directionality Problem – A problem encountered in correlational studies; the researchers find a relationship between two variables, but they cannot determine which variable may have caused changes in the other variable. Third Variable Problem – A problem that occurs when the researcher cannot directly manipulate variables; as a result, the researcher cannot be confident that another, unmeasured variable is not the actual cause of differences in the variables of interest. Components of Experimental Research Independent variable - The variable that gets manipulated Dependent variable - The variable that gets measured. “depends” on the independent variable Experimental group – Treatment groups; the participants in a study that receive the intervention. Control group – A comparison group; the participants in a study that receive no intervention or receive an intervention that is unrelated to the independent variable being investigated. Problems with Experimental Research Confounds - Anything that affects a dependent variable and may unintentionally vary between the experimental conditions of a study. Sample – A subset of a population. Selection bias - In an experiment, unintended differences between the participants in different groups. How to correct sample issues? Random samples Random assignment - Placing research participants into the conditions of an experiment in such a way that each participant has an equal chance of being assigned to any level of the independent variable. Good Research Requires Construct validity – The extent to which variables measure what they are supposed to measure. External validity – The degree to which the findings of an experiment can be generalized outside the laboratory. Internal validity – The extent to which the data collected in a study address the research hypothesis in the way intended. Reliability – The extent to which a measure is stable and consistent over time in similar conditions. Accuracy – The extent to which an experimental measure is free from error. Analyzing Data Descriptive statistics: Measures of central tendency Mean – A measure of central tendency that is the arithmetic average of a set of numbers. Median – A measure of central tendency that is the value in a set of numbers that falls exactly halfway between the lowest
and highest values. Mode - A measure of central tendency that is the most frequent score or value in a set of numbers. Variability – In a set of numbers, how widely dispersed the values are from each other and from the mean Standard deviation – A statistical measure of how far away each value is, on average, from the mean Range – The difference between the lowest and highest number in a set of numbers.