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
– Eye color
– Class standing
– 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:
– 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
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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 –
Transport Definition In an experimental study, the ___________ variable is usually deliberately manipulated. –
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
– 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.
- Spring '10