For each of the questions below, choose the correct answer(s) and provide justification in terms of why the other answer(s) are incorrect. Q2A. Which of the following are possible consequences of overfitting an ARIMA model? i. The model may have high bias. ii. The model may have high out-of-sample variance. iii. The model may have poor predictive performance. iv. All of the above

Suppose a researcher is interested in a new treatment plan for increasing CD4 cell count in immune-compromised patients with HIV. In order to investigate the new drug, the researcher gathers a group of 48 individuals with a mean CD4 count of 317 cells/mm3 after treatment with a standard deviation of 24.6. Test the hypothesis that the mean CD4 count has increased above the goal of 275 cells/mm3. Write out your hypotheses and correctly interpret your pvalue. (Use an alpha level of 0.01)

(Yi, X1i, X2i) satisfy the assumptions of the attachment. You are interestedin β1, the causal effect of X1 on Y. Suppose that X1 and X2 are uncorrelated.You estimate β1 by regressing Y onto X1 (so that X2 is not included in theregression). Does this estimator suffer from omitted variable bias? Explain.

the probability of reaching the wrong conclusion to 0.05 the probability of a Type II error equal to 0.05 the probability of reaching the correct conclusion equal to 0.05 the probability of a Type I error equal to 0.05 attached in ss below thanks

19. The White test test statistic is n*R² ~x²(S-1). Where is the R² in the test statistic measured? A. The original econometric model when estimated using the White Robust Estimator B. The average from all the auxiliary regressions estimated with each explanatory variable as a function of the other explanatory variables C. The original econometric model before any test of heteroskedasticity has been performed D. The auxiliary regression of residuals as a function of the explanatory variables generating the heteroscedasticity 20. With annual times series data of 50 observations, how many observations are available to estimate the consumption econometric model CONt = Bo+ ß₁DISPYt + B₂CONt-1+ut A. 50 B. 47 C. 45 D. 49 21. Suppose the estimated simple linear demand equation for single-game tickets for a major football league is q=4.58-0.51p where q is the number of tickets sold measured in thousands and p is the dollar price of a ticket. Further assume that the point of the means_is…

a) What is the logic of probability sampling? b) c) V. Distinguish between broad objective and specific objective. Write brief notes on each of the following, giving appropriate examples: Simple random sampling ii. Systematic sampling iii. Sampling frame iv. Variable Parameter