WGU C723 Quantitative Analysis Latest Update Rated A

WGU C723 Quantitative Analysis Latest Update Rated A Correlation the extent to which two variables are related (move together) Deterministic Relationships that are perfectly correlated are called (on the trendline) Trendline a straight or curved line superimposed on a scatter plot indicating the nature of the relationship between two variables Stochastic Relationships that are not perfectly correlated Multiple R is also known as the correlation coefficient. The magnitude and direction of the association between the actual and predicted y-Value R Squared is also known as the coefficient of determination. It represents the % variation in the outcome variable explained by all independent variables. Adjusted R Squared this statistic is used to decide whether adding a variable is beneficial to the model, and to what extent. A good indicator of dispersion for the entire model. Standard Error an estimate of the error in the entire model. Smaller indicates there is less unexplained variation in the outcome variable Regression SSR Residual SSE Total SST Significance F the probably the results of the entire model occurred by random chance. The probability of the coefficients for all predictor variables is zero. Standard Error An estimate of the dispersion in the coefficient. Alternatively, an estimate of the coefficient's inferred standard deviation 5 Assumptions Underlying Linear Regression Analysis 1. the relationship between y & X is linear 2. The expected value of regression errors is 0 3. The variance of regression errors is constant 4.Regression errors are normally distributed 5.Regression errors are independent. (they do not exhibit a pattern) Prediction Forming an inference / conclusion inside the range of the x-variable Forecast forming an inference / conclusion outside the range of the x-variable Outlire a data element that does not belong in the dataset Histogram A_______is used to organize numerical data into ordinal categories. Scatter Plot A________can be used to plot time series data values. Histograms ___________provide a picture of how a sample is distributed by collapsing