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PSYCH 210 NOTES HW 1 The Scientific Method Uses intuition or authority to find questions Asks empirical questions o Questions that can be tested o Number quantitative information Data driven Objective o Evidence used to support conclusions o Findings can be verified Theory Deduction Deduction Hypothesis Hypothesis Induction Induction Theory A Loop Recall Deductive Reasoning general specific Inductive Reasoning specific data general theory Goals of Psychological Research Describe Behavior Predict Behavior Explain Behavior determine its causes Control Behavior Statistics refer to a set of mathematical procedure for organizing summarizing and interpreting information What is Statistics Purpose of Statistics Communicate the results to others stats are used to organized and summarize the info from the research study Answer general research questions Two Branches of Statistics 1 Descriptive Stats used to organize summarize and communicated data o The goal is to reduce a large amount of info into a smaller set o Ex the average exam score was 78 and scores ranged of bullet points between 55 and 99 2 Inferential Stats use samples to draw conclusion about a population o Did results come from fluke or random chance A pop is an entire set of individuals that possess some attribute that we are interested in studying Ideally we want to used the results of our study to describe this However it is not usually feasible to collect data from the entire Population larger group population Sample population Parameters and Statistics A sample is a subset of individuals selected from a population We seek to a have representative sample Random samples tend to be the best representative of the Parameters Numerical values summarizing population data Statistics Numerical values summarizing sample data Population means parameter Sample means statistics Variables any observation of a physical attitudinal or behavioral characteristic that can take on different values Can be classified as several types o Discrete or Continuous Nominal ordinal interval ratio o Independent Dependent Cofoundinal Discrete Variable Separate invisible categories Categorical Continuous Variable divisible into an infinite number of fractional parts Quantitative Measurement Scales Nominal Scales Discrete o set of categories that have different names o No quantitative information at all Ex gender Ordinal Scale Discrete o Set of categories that are organized in a ordered sequence Ex race order 1st 2nd 3rd o Do not know how long in between each interval Interval Scales Continuous o Ordered categories that are all intervals of exactly the same size o Has an arbitrary zero point Ex Fahrenheit Ratio Scale Continuous o An interval scale with an absolute zero point Ex minutes miles heart rate Likert Scales Likert scales are very common in psychology Tend to treat them as interval scales How much do you like 1 Strongly Disagree 2 Disagree 3 Slightly Disagree 4 Neutral 5 Slightly Agree 6 Agree 7 Strongly Agree Independent Variable IV AKA Exploratory Variable Can be manipulated or observed Dependent Variable DV AKA Response Variable Outcome Confounding Variable AKA Lurking Variable Systematically varies with IV so that we cannot determine which variable is influencing the DV Hypothesis Testing and Operation Definitions Define a variable in terms of operations used to measure or manipulate it Define o Love o Aggression o Depression o Happiness o Helping constant reliable Best to use multiple operational definitions when measuring a Creating and Assessing Variables Reliability consistent results Doesn t have to be right but is still Validity extent the test measures what it is supposed to measure Types of Research Designs Experiments o random assignment of participants Non Experiment Quasi Experiments o random assignment not possible Correlation Research o No manipulation of IV o Examine how two variables vary together o No causation Between Subjects Designs Each level of the IV has one group o Or each participant is in one level of the IV Benefits Problems o Eliminates many possible confounds o Requires lots of participants Within Subjects Design Ex studying which genre of music you listen to before a test and how it effects you Each participant gets each level of the IV Benefits needs less participants Problems o Order effects listening to one type of music may influence your score for the next rounds o Testing effects getting used to the test o Fatigue effects getting tired of it HW 2 Due 9 9 13 Descriptive Stats Organize summarize and communicate numerical info Frequency distributions are a type of descriptive stats Frequency Distributions Our data consists of several raw scores A frequency distribution describes the pattern of a set of numbers o Displays counts or proportion for each possible variable Frequency table shows how many raw scores were at each value o Values listed in 1 column o Number of individuals with scores at that value in second column Structured as o Table scores ordered high to low List scores low to high add up each individual score add percentage column o Graph scores ordered low to high Two elements o Categories or original measurement scale o Frequency or number of individual categories Grouped Frequency Tables Appropriate for continuous data Represent ranges of values instead of each possible value o Round down highest and lowest values and find the range o Add one to the range o Determine the interval easily understood whole number o Bottom range should be a multiple of the interval Ex High 100 Low 46 round down to 40 Histograms X Axis variable Y Axis frequency Center bars on value whose frequency is being represented o Use middle of interval for grouped frequencies Frequency Polygon Constructed like a histogram except with data points and lines Create hypothetical zero points for each end of the data range Instead of bars histograms dots to connect lines on a graph HW 3 Shapes of Frequency Distributions Most common is the Normal Distribution Many phenomena are normally distributed o Bell shaped o Symmetric o Unimodal o Height o IQ o SAT or ACT Scores Skewness Paper Notes Asymmetrical distribution Skewed distributions have scores piled up at one end and taper off at the other o The section where the scores taper off is called the tail of the distribution Positively Skewed tail on the right hand side o OLI Skewed right distribution Negatively Skewed tail on the left hand side o OLI Skewed left distribution Common

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