Review for Psych Stats Exam 1 PDF

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This is a review for exam 1 in psychological statistics with Cohen-Shikora. It includes basic descriptive statistics along with null hypothesis significance testing....

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Review for Psych Stats Exam 1 Variables - Independendent - Dependent - Extraneous/Confounding 1. Levels of Measurements a. Nominal - Category, none are “better” than others b. Ordinal - Ranked in order but no interval c. Scale - Defined intervals 2. Continuous or Discrete a. If a value can take on any value between two specified values otherwise it is discrete 3. Reliability and Validity a. Consistency b. Are we measuring what were supposed to measure? NHST: Null Hypothesis Significance Testing 1. Nothing happened in the experiment 2. How to Perform: a. Assume there is no condition b. Test likelihood to obtain our data given no actual difference c. Draw conclusion 3. P-Value: a. How likely this would happen if we did nothing b. 0.05 is the cut off- if something is more likely than 5% (p value accept the null Descriptive Statistics Vs. Inferential Statistics 1 Descriptive: Summary of data from a sample

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i. Scale IV and DV c. Line Graphs i. Nominal/ordinal IV when you want to emphasize chang d. Scatterplots i. Two scale variables Consider what you want to emphasize, label axes, include figure capt indication of error, maximize data:ink ratio a. When do you not need error? i. When you are plotting single data points Frequency Distributions: a. These show raw data for one variable at a time and proportion of a score b. They are important to see pattern of our data, make sure there Difference in Frequency Distributions and Bar Graphs a. Frequency Distributions i. Distribution of one variable ii. Continuous data with values/ intervals on the x axis iii. No error bars Types of Distributions a. Normal i. mean=median=mode b. Positive: tail points to the positive direction i. mean>median>mode c. Negative: tail points to negative direction i. mean...