PSYC 311 Unit 8 Exam Questions With All Correct Answers 2025 Marking Scheme

PSYC 311 Unit 8 Exam Questions With All Correct Answers 2025 Marking Scheme Two variables increasing and decreasing together is to _____ as two variables moving in opposite directions is to _____. - Answer- a positive relationship; a negative relationship Causation implies _ - Answer- correlation If a correlation coefficient that you expected to be fairly high turns out to be very low, you should investigate whether there is a: - Answer- restrictive range on one or both variables and a curvilinear relationship between the variables. The proportion of variance accounted for by a correlation between two variables is determined by _________. - Answer- r squared _ is called the coefficient of determination. - Answer- r squared (T/F): Since r is so widely used, it is appropriate to calculate r for nonlinear data. - Answer- false Correlation is commonly used to measure straight-line or _ relationships. - Answer- linear Pearson product-moment correlation is a _ correlation - Answer- bivariate In a Pearson correlation, both x and y are _ variables - Answer- continuous What scales are appropriate for the Pearson correlation? - Answer- interval and ratio null hypothesis for Pearson correlation - Answer- correlation in the population is zero alternate hypothesis for Pearson correlation - Answer- correlation in the population is NOT zero How do you determine significance of a Pearson correlation? - Answer- compare p value to alpha practical significance is determined by _ size - Answer- effect r=.10 is a _ effect - Answer- small r=.30 is a _ effect - Answer- medium r=.50 is a _ effect - Answer- large what does r measure? - Answer- correlation What is the coefficient of determination? - Answer- r squared how to find r squared - Answer- square r value, then multiply by 100 why is r squared called the coefficient of determination? - Answer- it measures the proportion of variability in one variable that can be determined from its relationship with the other variable what does Spearman correlation measure? - Answer- the relationship between variables measured on ordinal scales the Spearman correlation can be used as a alternate to the Pearson correlation when_ - Answer- a consistent relationship is expected, regardless of the form of the relationship Point-biserial correlation measures the relationship between - Answer- a continuous and a dichotomous variable Phi-coefficient measures the relationship between _ - Answer- two dichotomous variables Phi-coefficient converts each variable to numerical values, _ and _ - Answer- 0; 1 When a correlational study demonstrates a relationship between two variables, it allows researchers to use knowledge about one variable (called the _ variable) to help predict or explain the second variable (called the _ variable) - Answer- predictor; criterion third-variable problem - Answer- It is always possible that a third, unidentified variable is controlling the two variables and is responsible for producing the observed relation. directionality problem - Answer- A correlational study does not determine which variable is the cause and which is the effect. (T/F): If r = -1.00, the relationship is imperfect. - Answer- false (T/F): The value of r obtained by calculating the correlation between X and Y is the same as the correlation between Y and X. - Answer- true