1_intro_lecture - Statistics& Research General...

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Unformatted text preview: Statistics & Research General Background Importance of Statistics – Numbers are powerful – Understanding research – Conducting research Software – SPSS – Excel Variables Variable – something that can take on more than one value Independent variable – explains or causes Dependent variable explained or effect Examples of Variables Example – Sex – Eye color – Class standing – Age – Height – Weight – Visualization – SAT­Verbal – Curiosity Possible values – Female, male – Blue, brown, green – Fr, soph, jr., sr. – 6, 19, 25, 70 (years) – 60, 72, 84 (inches) – 79, 101, 220 (lbs) – 1.5, 2.0, 3.0 (secs) – 500, 600 (scores) – 40, 50, 60 (scores) Population & Sample Population – the complete collection; everyone of interest (adults in U.S.; students at USF) Sample – a subset of the population (students at USF are a sample of adults in U.S.; student in this class are a sample of students at USF). We usually do research with a sample. Quick and cheap. Using the population is too costly. Parameter & Statistic Parameter – a numerical summary of the population (average age of students at USF if students at USF is the population). Statistic – a numerical summary of a sample (average age of students in this class if students at USF is the population). Sample statistics serve 2 purposes: – Descriptive – Inferential Relations among Terms Sample 10 people Population all adults in U.S. Statistic mean Parameter mean Symbol English (Arabic) M or X Greek (mu) µ Review Definitions Population Sample Parameter Statistic Types of Studies Design – set of data collection procedures Experiment (Experimental study) – IV manipulated; often random assignment Correlational study – IV measured, not manipulated Experiment Independent Variable – schedule Dependent Variable – Rph Extraneous Variable(s) – Sex of experimenter – marble Another Example Brannick wants to know if be r consum e ption the Brannick night be an e is re d to e score the fore xam late xam s f ollowing day. Heasks e stude taking an e ach nt xam t henum r of be rs the had thenight be and be e y fore calculate thetotal scoreto se re s e lationship. calculate Experimental or correlational? IV? DV? Extraneous (nuisance)? Definition The way in which a study is set up and conducted is known as the study’s – – – – Conduct Design Operation Transport Definition In an experimental study, the ___________ variable is usually deliberately manipulated. – – – – Dependent Extraneous Independent Nuisance Definition We want to know about a large group of people, but we can only afford to study a small group of people. In statistics, the larger group is called the – Focus – Generalization – Population – Sample ...
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This note was uploaded on 05/21/2011 for the course PSY 3204 taught by Professor Brannick during the Spring '10 term at University of South Florida.

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