Exam # 2 Study Guide Lectures: 9-14Lecture 9What are the three special types of validity?1. Content: Property of a test such that the test items sample the universe of items for which the test is designed2. Criterion: Any variable one wants to “predict” by measuring another (can be concurrent or predictive)3. Construct: abstract concept made up of interrelated variables; The results of measurement follow from the theory/hypothesis; The results correlate with other, related measuresLecture 10Define Z-scoreThe Z-score is the number of standard deviations that a given value x is above or below themeanReview the formulas on Dr. Thrasher’s presentationsHow are quartiles partitioned?1. First quartile: Q1 2. Second quartile: Q23. Third quartile: Q3Lecture 11Define Exploratory Data Analysis (EDA).EDA is the process of using statistical tools (such as graphs, measures of center, and measures of variation) to investigate data sets in order to understand their important characteristics KIN 4310What is an outlier? What are its’ effects?An outlier is a value that is located very far away from almost all of the other values. It can have a dramatic effect on the mean, the standard deviation, and the scale of a histogram. What is the importance of the probability value (p)?It is used to state how confident we can be about the existence of a particular statistical relationship. A value of 1 indicates the event is certain to occur. A value of 0 indicates the event is impossible. Lecture 12List the steps of the Scientific Method with respect to inferential statistics.1. Assume that H0 is true2. Select an appropriate sample3. Perform experiment (or make observations)4. Collect Data5. Given that H0 is true, is it likely that you would end up with the data that you got? YES: Fail to reject H0 ; NO: Reject H0 - The evidence is conclusiveDescribe Type I and Type II errors.1. Type I error is the mistake of rejecting the null hypothesis when it is true; The symbol (alpha) is used to represent the probability of a type I error2. Type II error is the mistake of failing to reject the null hypothesis when it is false; The symbol (beta) is used to represent the probability of a type II errorLecture 13What are the 4 steps of a T-test?1. Step 1: Calculate the t-value2. Step 2: After you know the t-value, you must determine the degrees of freedom (df)3. Step 3: Determine the critical value of t4. Step 4: Compare your t-value to the critical valueDescribe the critical value method.Based on a statistical model, find a value that partitions 95% of the “usual” values from 5% of the “unusual” valuesLecture 14No lecture materialIn-class