Statistics for Psychology Test #1

# Statistics for Psychology Test #1 - S tatistics for...

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Statistics for Psychology Test I Study Guide Introduction/Chapter 1 - goal of any science is to build an organized body of knowledge to develop valid and reliable explanations for the phenomena within its domain - most behavioral research concerns the relationship between variables o has different values ( levels) for different individuals - variable: characteristics of persons or objects that vary from person to person or object to object o CHANGE - Constant: characteristics that remain constant from person to person or object to object o DO NOT CHANGE - in an experiment, we manipulate/ “create” independent variable (IV) o must have at least two levels - in an experiment, we observe/record the dependent variable (DV) - hypothesis o prediction about results of an experiment o predict how IV will affect DV o often derived from theory - Theories contain o Hypothetical construct: hypothetical concept used in theories to organize observations in terms of underlying mechanisms o Operational definitions: defines a construct in terms of specific operations/procedures; defines the measurement - Population o The entire group a researcher wants to study o Every single individual person or animal o Set of all individuals of interest in a particular study - You the researcher define the population of interest. - Usually it’s impossible to study a whole population so we study a sample of the population o Sample: subset/set of individuals selected from the population o There are different ways to draw samples ( “sampling” ); usually intended to represent the population - goal of research is to describe the relationships in a population - a “good sample” means:

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must be representative of the population o relevant characteristics of the sample must accurately reflect the relevant characteristics of the population obtain a representative sample by getting a random sample - Measurement o In psych we measure behavior o Assignment of numbers to a behavior - Goal: Not to discuss conclusions about a sample but to generalize from sample to population - parameter: a measurement or characteristic of a population - statistic: a measurement or characteristic of a sample - We use sample statistics to estimate population parameters. - We use scores in the sample to estimate the scores we would expect to find if we could measure the whole population - Usually statistics from a sample will not be exactly the same as a corresponding population parameter o Difference = sampling error - In psychology we measure behavior changes in o Behavior o Variability in behavior o Difference in behavior under different conditions - Measurements o Assignment of numbers to persons, objects, events o Four levels of measurement Nominal Ordinal Interval Ratio - Nominal (Categorizing/naming) o Simplest form of observation o Perceive that two objects are similar or dissimilar objects perceived to be similar are assigned to the same classification can have subclasses too o examples: GOO #, SSN, zip code, number on jersey
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## This note was uploaded on 10/24/2010 for the course PSYCH 251 taught by Professor Ruddy during the Spring '10 term at SUNY Geneseo.

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Statistics for Psychology Test #1 - S tatistics for...

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