Correlation and Regression

Question 1

A _____ is a mathematical index that describes the direction and magnitude of a relationship.

Answer 1

correlation coefficient

Question 2

The _____ correlation coefficient is a ratio used to determine the degree of variation in one variable that can be estimated from knowledge about variation in the other variable. The correlation coefficient can take on any value from - 1.0 to 1.0. It is the most commonly used because most often we want to find the correlation between two continuous variables. Continuous variables such as height, weight, and intelligence can take on any values over a range of values.

For example, on average, as height in people increases, so does weight.

Answer 2

Pearson product moment

Question 3

_____ is a method of correlation for finding the association between two sets of ranks. The _____ coefficient is easy to calculate and is often used when the individuals in a sample can be ranked on two variables but their actual scores are not known or have a normal distribution.

For example, if the first student’s physics rank is 3 and the math rank is 5 then the difference in the rank is 3. In the fourth column, square your d values. The Spearman’s Rank Correlation for this data is 0.9 and as mentioned above if the ⍴ value is nearing +1 then they have a perfect association of rank.

Answer 3

Spearman’s rho (r)

Question 4

The _____ expresses the relationship between a continuous variable and an artificial dichotomous variable. For example, the biserial correlation might be used to assess the relationship between passing or failing the bar examination (artificial dichotomous variable) and grade point average (GPA) in law school (continuous variable).

_____ is a correlational index that estimates the strength of a relationship between an artificially dichotomous variable (X) and a true continuous variable (Y). Both variables are assumed to be normally distributed in their underlying populations.

Answer 4

Biserial correlation (rbis)

Question 5

_____ is the amount of decrease observed when a regression equation is created for one population and then applied to another.

Answer 5

Shrinkage

Question 6

The best way to ensure that proper references are being made is to use the regression equation to predict performance in a group of subjects other than the ones to which the equation was applied. Then a standard error of estimate can be obtained for the relationship between the values predicted by the equation and the values actually observed. This process is known as _____.

Answer 6

cross validation

Question 7

_____ analysis considers the relationship among combinations of three or more variables. For example, the prediction of success in the first year of college from the linear combination of SAT verbal and math scores is a problem for multivariate analysis.

Answer 7

Multivariate

Question 8

When the task is to find the linear combination of variables that provides a maximum _____ between categories, the appropriate multivariate method is _____ . An example of _____ involves attempts to determine whether a set of measures predicts success or failure on a particular performance evaluation

Answer 8

discriminant analysis