Descriptive Analytics I: Nature of Data, Statistical Modeling, and Visualisation - Regression Modelling for Inferential Statistics
6 important questions on Descriptive Analytics I: Nature of Data, Statistical Modeling, and Visualisation - Regression Modelling for Inferential Statistics
What is regression and what statistical purpose does it serve?
It can be used for:
- hypothesis testing (theory building): investigating potential relationships between different variables. It can reveal the strength and directions of relationships between a number of explanatory variables and the respons variable.
- Prediction/forecasting: estimating values of a response variable based on 1 or more explanatory variables. The equation is used to predict.
What are the commonalities and differences between regression and correlation?
regression: attempts to describe the dependence of a respons var. on 1 (or more) explanatory vars. Implicit assumption that there is a 1-way causal effect.
What is OLS? How does OLS determine the linear regression line?
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List and describe the main steps to follow in developing a linear regression model?
What are the most commonly pronounced assumptions for linear regression?
Independence (of errors): the errors of the response variable are uncorrelated of each other.
Normality (of errors): the errors of the response variable are normally distributed
Constant variance (of errors): the errors of the response variable have the same variance. Assumption is invalid if resp.vars. over a wide enough range.
Multicollinearity: the explanatory variables are not correlated.
What is time series? What are the main forecasting techniques for time series data?
naïve forecast: today's forecast is the same as yesterday's actual
ARIMA: very complex: combination of AutoRegressIve and Moving Average patterns
Averaging methods: simple average, moving average, weighted moving average,...
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