Description
- Calculate the mean and standard deviation of a dataset X = [12, 15, 18, 21, 24] without using any statistical software. Explain the importance of these measures in descriptive statistics.
- Define the concept of heteroscedasticity in a regression context. What are the potential consequences of heteroscedasticity on the validity of regression results, and how can you address it?
- Given a time series dataset, explain the difference between stationarity and non-stationarity. Provide an example of a test or diagnostic plot that can help determine stationarity.
- Describe the difference between Type I and Type II errors in hypothesis testing. How can you minimize the risk of making these errors in a hypothesis test?
- Explain the concept of ceteris paribus in regression analysis. Why is it important to hold other variables constant when interpreting the coefficients of independent variables?
- Calculate the coefficient of correlation (Pearson’s correlation coefficient) for two variables X and Y using the following data: X = [3, 4, 5, 6, 7] and Y = [6, 7, 8, 9, 10]. Interpret the correlation value.
- Discuss the concept of the omitted variable bias in regression analysis. Provide an example of how omitting a relevant variable can lead to biased coefficient estimates.
- What is the purpose of the Durbin-Watson statistic in regression analysis? How does its value indicate the presence or absence of autocorrelation in the residuals?
- Describe the differences between cross-sectional data and time series data. Provide examples of research questions that are better suited for each type of data.
- Explain the concept of the Granger causality test in time series analysis. How does it help determine if one time series can predict another? Provide an example scenario where Granger causality testing is relevant.