A student has grades on three examinations of 76, 80, and 72. What must the student earn on a fourth examination to have an average of at least 80?
Statistics for Behavioral Sciences EXAM 4 Study Guide Chapters 9 – 11 Chapter 9 – Linear Correlation #1 rule – correlation does not imply causation! Perfect Correlation – if there is a change in variable x, there will be a proportional change in variable y. Correlation is NOT about 2 variables having the exact same value – it’s about 2 variables having the same position/location on the data set. Z scores show location of scores in distribution so perfectly correlated variables will have the same z scores. Pearson’s Correlation Coefficient (r) – a measurement of linear correlation. r = (+/- 1) when there is a perfect correlation As r approaches 0, there is lack of correlation – more error. Drawing circles, or envelopes, around points o