WGU C955 Applied Probability and Statistics - - Module 6: Correlation And Regression with Complete Solutions!

lurking variable - ANSWER-A variable that is not included in an analysis but that is related to two (or more) other associated variables which were analyzed. observational study - ANSWER-The researcher observes if there is an association between variables. There is no treatment or control group. sampling method - ANSWER-The technique used to select people within the sampling frame. correlation - ANSWER-An observed relationship between two quantitative variables. While this is most commonly a linear relationship, it does not need to be. Note that observing a relationship does NOT imply that there is a meaningful causal link between the variables. coordinate plane - ANSWER-A tool for graphing consisting of a horizontal x-axis and a vertical y-axis. correlation coefficient - ANSWER-A measure of the linear relationship between two attributes. The numerical value demonstrates how closely the attributes vary together. Correlation coefficients near -1 and +1 have strong linear correlation, while a correlation coefficient near 0 has weak (or no) linear correlation. linear interpolation - ANSWER-Estimation using the linear regression equation in between known data points. least squares - ANSWER-A technique for finding the regression line. voluntary sample - ANSWER-Researchers invite everyone in the sampling frame to participate. Individuals who voluntarily respond comprise the study sample. scatterplot - ANSWER-A graph that uses dots on a coordinate plane to show the relationship between variables. representative sample - ANSWER-A subset of the population with similar characteristics to the entire population. significance level - ANSWER-The p-value cutoff for statistical significance. Any p-value below the set significance level is considered statistically significant. hypothesis test - ANSWER-A statistical test that tells us whether a result is significant. slope-intercept form - ANSWER-A common format for the equation of a line: y = mx + b, where m is the slope and b is the y-intercept. significant difference - ANSWER-A measurable difference between two groups or samples that reflects a real difference, rather than the difference being by chance. Simpson's Paradox - ANSWER-A counterintuitive situation in which a trend in different groups of data disappears or reverses when the groups are combined. negative correlation - ANSWER-A linear relationship between two quantitative variables in which the dependent variable increases as the independent variable decreases. causation - ANSWER-A relationship of cause and effect between two or more variables.