Statistics and correlation How might we use stats in psych?

Statistics How do we describe data? -Gather raw data -Frequency Distribution= number or frequency of a behavior. - X-axis=data you are graphing -Y-axis= represents frequency Histograms= Bar graphs

Measures of Central tendency Mode- The score that occurs most often Why Use? Median-the middle score How do we calculate median?

Calculator from Notebook Use calculator page here

Calculating Mean…. Mean-The average of all scores How do we calculate mean? How can mean be distorted? Outliers= example Demo- Positive and negative skew

Measures of Variation The Wechsler IQ scale Range- gap between high and low scores Standard deviation- measures the degree to which scores deviate from one another EX: IQ

Correlation -Handout CCorrelation Coefficient AA statistical measure that indicates how well either factor predicts the other Correlation coefficient Indicates direction of relationship (positive or negative) Indicates strength of relationship (0.00 to 1.00) r = +.37

Understanding Correlations NOT Cause and effect Frosted Flakes prevents cancer, oatmeal causes cancer ( Good News Survey) TV watching is linked to childhood obesity

Illusory Correlation The perception that a relationship exists between two variables when no relationship is present. Ex:

Correlation Research Advantages: Can examine a relationship between two variables Saves $ and time Can allow one to make predictions Allows use of preexisting data Disadvantages: Cant establish CAUSE & EFFECT Prone to inaccurate reporting ( survey) Confounding variables Cant manipulate variables

Advantages/Disadvantages of other Research Methods Experiments Case History

Advantages & Disadvantages: Experiment Advantages: CAN establish cause and effect Can actively manipulate variables via operationalization of variables Can use double blind procedure Can distinguish between real and placebo effects Can be replicated

Disadvantages: Experiments may be artificial or contrived Hard to establish controls, eliminate confounding variables Probability of bias $ and time consuming

Others Methods of Research: Case History= A biographical review of patients relevant history. Advantages: - In depth info - Rare Phenomena or unusual cases - Preexisting cases don’t involve ethics - Time and $ Factors

Case History: - Disadvantages: - Can’t generalize results - Inaccurate reporting - no cause and effect

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Naturalistic Observation:  Naturalistic Observation  observing and recording behavior in naturally occurring situations Advantages: natural setting Disadvantages: cant generalize, variables are not controlled

Description SSurvey tthe self-reported attitudes or behaviors of people rrepresentative, random sample of people Limitation: Intentions are not always translated into action

COMPUTER LAB TOMMOROW Lab on correlation and stats Show website