Exam 1)PSYC 3402 Exam 1 Study Guide: PSYC 3402 Exam 1: Questions & Answers: Latest Updated

What is a weighted mean? (Ans- -When a data set contains several repeated values, this may be used simplify the calculation (instead of adding each value together) -It may be used to calculate the mean of multiple data sets where only the mean and frequency (n) of each data set is known Equation: Σ(x*w) / Σ(w) Key: x = score, w = frequency, x*w = score multiplied by frequency Practice: What is the mean, median, and mode of the following numbers? 7, 6, 9, 11, 4, 12, 5, 4 (Ans- n = 8, mean = 7.25 , median = 6.5, mode = 4 What are the measures of variability? (Ans- -Range -Variance -Standard DeviationWhat is the range? (Ans- The total difference between scores What is the variance? (AnsThe average variability between scores and the mean What is the standard deviation? (Ans- -The standardized average variability about the mean -The square root of the variance How do you calculate the variability of the range (exclusive)? (Ans- -Subtract the lowest value (score) from the highest r = h - l (r = range, h = high score, l = low) r = h - l + 1 (for the inclusive range)How do you calculate the variability of the variance? (Ans- s2 = Σ (X- ¯