Psychological Statistics II Flash Cards

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Title: Psychological Statistics II
Description: Flashcards from Psych Stat II course I took in Fall 2007.
Number of Cards: 18
Save Count: 1
Author: mdgreen25
Created: 2007-08-28
Tags: stat terms
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    • Question
    • Answer
    • Side 3
    • What are three important reasons why a knowledge of statistics is essential for anyone majoring in psychology, sociology or education?
    • To understand the professional literature, to understand the rationale underlying research in behavioral science and to carry out behavioral science research.
    • Descriptive Statistic
    • A statistic used to summarize or describe the characteristics of set of data in a clear and convenient fashion.
    • Inferential Statistic
    • A statistic used to make possible inferences about what is happening in the population based on what is observed in a sample from that population.
    • What must behavioral science researchers use inferential statistics?
    • The time, cost and resources it would take to gather data from a whole population would be too much. Better to just use a sample.
    • Population
    • Is the group that consists of all the cases of interest
    • Sample
    • Any subgroup drawn from the specified population.
    • Statistic
    • A numerical quantity that summarizes some characteristic of a sample.
    • Parameter
    • The corresponding value of the characteristic(statistic) in the population.
    • Why is it important to specify clearly the population from which a sample is drawn?
    • If the sample does not correctly represent the mean, then the statistic will not match the parameter of the population.
    • Interval Scale
    • A scale used for physical measurement, with fixed units.
    • Ratio Scales
    • A scale in which there is an absolute zero, with nothing there.
    • Nominal Scales
    • Categories, with no numerical precision.
    • Ordinal Scales
    • Scales in which the data is ranked.
    • Qualitative Data
    • No obvious order to the categories and no regular intervals between them.(Nominal)
    • Quantitative Data
    • Data with the interval property, and precise measurement is needed. (Ratio/Interval)
    • What is the difference between observational and experimental studies?
    • Experiments involve measuring dependent variables that are expected to vary somewhat as a function of the different levels of one or more independent variables created by the researcher. Observational research involves comparing dependent variables to each other since we are not manipulating variables.
    • Why is summation notation used by statisticians?
    • Often times there is a lot of data to compile, and its easy shorthand for A+B+C+D... Its also frequently used in statistical work.
    • What are the eight rules involving summation notation?
    • The same total should be reached regardless the scores are added and subtracted. The Sum of multiplying XY is not the same as the Sum of X multiplied by the Sum of Y. Same for Squares. If you take the sum of a constant, it is just the constant N amount of times. The sum of X plus the Sum of a constant is just Sum of X plus Constant N; as well as subtraction.