LECTURE 10 Flashcards
What is the formula for a straight line used in regression analysis?
Y=bX+a
In the formula
Y=bX+a, what does
Y represent?
Criterion/response variable or dependent variable (e.g., salary)
In the formula
Y=bX+a, what does
b represent?
The slope of the line (based on Pearson’s r)
In the formula
Y=bX+a, what does
X represent?
Predictor/independent variable (e.g., years of experience)
In the formula
Y=bX+a, what does
a represent?
The constant or intercept (e.g., starting salary)
What is the purpose of a regression analysis?
To predict variance in a dependent variable from independent variables.
What does the adjusted
R^2 indicate in regression output?
How much variance in the dependent variable is accounted for by the independent variable.
What does a p-value of less than 0.05 indicate in regression analysis?
The model is statistically significant.
What is the difference between Pearson and Spearman correlations?
Pearson uses continuous data, Spearman uses ranked/ordinal data.
What are the assumptions of bivariate regression?
Normally distributed DV, independent data, interval/ratio predictors or dichotomous nominal.
What does the unstandardized beta coefficient represent?
Predicted change in DV for one unit change in IV.
What is the main focus of regression analysis compared to correlation analysis?
Prediction of variance.
How is a regression line described?
The best-fitting line that minimizes error.
What does F-statistic represent in regression output?
A test statistic to assess model fit.
What is a dichotomous variable?
A variable with two categories, e.g., gender.
Why is decimalization convention used in p-values and correlations?
To indicate the restricted range of values.
What is the significance of a model’s direction in regression?
Indicates whether the relationship is positive or negative.
What does the term “criterion variable” refer to?
Dependent variable (outcome).
What is the purpose of the line of best fit in regression?
To make predictions for observed and unobserved data points.
What is an interval variable?
A variable with equal intervals but no true zero (e.g., temperature in Celsius).
What does “nominal variable” mean?
A variable representing categories without a specific order.
What is a ratio variable?
A variable with equal intervals and a true zero (e.g., height, weight).
What is a key difference between multiple and bivariate regression?
Multiple regression uses more than one predictor variable.
What is Cramer’s V used for?
Measuring effect size in Chi-square tests.
What does
r represent in correlations?
The correlation coefficient (Pearson).
What is the purpose of Chi-square tests?
To determine the association between categorical variables.
What is skewness in data distribution?
Measure of asymmetry in data.
Why is Spearman’s
r used?
For rank-ordered data.
What is the meaning of the adjusted
Rsquared value?
Proportion of variance explained, adjusted for number of predictors.
How is “effect size” typically reported?
Alongside test statistics, such as Cramer’s V or
r
What is the role of standard error in regression?
Measure of spread and accuracy of the beta coefficient.
What is interpolation in regression?
Predicting within the range of observed data.
What is extrapolation in regression?
Predicting beyond the range of observed data.
What does the p-value signify in hypothesis testing?
Probability of observing the data if the null hypothesis is true.
What does “normally distributed DV” mean in regression assumptions?
The dependent variable follows a bell-shaped curve.
Why do we report effect sizes with significance testing?
To provide context on the magnitude of the association.
What is meant by “independent data” in regression assumptions?
Each participant contributes only one data point.
How is variance explained in multiple regression?
By including additional predictor variables.
Why might regression be preferred over correlation?
It allows for prediction, interpolation, and extrapolation.
