Introduction to Psychology

Introduction to Psychology Measures of Variability - To describe a set of data, researchers want to know, not only the typical score, but also whether the scores cluster together or vary widely. Measures of variability capture the degree of variation or spread in a distribution of scores. The simplest but least informative measurement is the range, which is the difference between the highest and lowest scores in a distribution. A more important statistic is the standard deviation which takes into account howmuch each score in a distribution differs from the mean. Inferential- Descriptive statistics allow researchers to efficiently summarize data, but researchers typically want to go beyond mere description and draw inferences (conclusions) from their data. Inferential statistics tell us how confident one can be in making inferences about a population, based on findings obtained from a sample. • Null Hypothesis- A null hypothesis is a hypothesis that proposes no relationship or difference between two variables. • Alternative Hypothesis- Proposes a relationship between two or more variables. • Statistical Significance- Means that it is very unlikely that a particular finding occurred by chance alone. Psychologists typically consider results to be statistically significant only if the results could have occurred by chance alone in fewer than 5 times in 100. 1.4 Psychological Specialties Psychology is the scientific study of behavior and the mind. The term ‘behavior’ refers to actions and responses that we can directly observe, whereas the term ‘mind’ refers to internal states and processes, such as thoughts and feelings that cannot be seen directly and that must be inferred from observable, measurable responses. Because psychologists’ study biological, psychological, and environmental factors that affect a wide array of behaviors, psychological science intersects with many other disciplines; and many subfields and areas of specialty have developed. • Clinical Psychology- The study and treatment of mental disorders. Many clinical psychologists diagnose and treat people with psychological problems in clinics, hospitals, and private practice. Some are also scientists who conduct research on the causes of mental disorders and the effectiveness of various treatments. • Biopsychology- Focuses on the biological underpinnings of behavior, examining how the brain processes, genes, and hormones influence our actions, thoughts, and feelings. • Developmental Psychology- Examines human physical, psychological, and social development across the life span. • Experimental Psychology- Focuses on basic processes such as learning, sensory systems, perception, and motivational states. Most research in this field involves laboratory experiments, often with nonhuman animals. • Industrial-organizational Psychology- Examines people’s behavior in the workplace. • Psychometrician- Practices the science of measurement, or psychometrics. The term psychometrics refers to the measurement of an individual's psychological attributes,

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