Show your work and clearly explain each step (and your answer). You may use only
ID: 3050164 • Letter: S
Question
Show your work and clearly explain each step (and your answer).
You may use only a pen, paper, and simple calculator.
3. QUESTION 3 20 pts A researcher obtained data on infant mortality (deaths within one year of birth per 1000 births) in the United States from 1920 2000. A scatterplot with the least squares regression line for the data is shown below. The residual plots for the regression model are also provided Residuals vs Fitted Normal O-a 1800 2000 2 40 Fed sues (a) Analyze the residual plots. Are the conditions for a simple linear regression model satisfied? If there are any conditions that cannot be assessed with the provided plots, state what they are (b) A transformation was applied to the response. A scatterplot of the trans- formed data with the least squares regression line is shown below. Thie residual plots for the regression model are also provided. Analyze the residual plots.Explanation / Answer
a)From the first scatter plot, it seems that hardly any point falls on the line which violates the assumption of linearity.
In the second plot, there seems to be a pattern in the residual vs. fitted plot which indicates the presence of heteroscedasticity violating the assumption of homoschedasticity.
The third plot indicates that the residuals don't really fall on the Q-Q line violating the assumption of normality of residuals.
The additional plots which are required are residuals vs. predictors plot and ACF plots for detecting autocorrelation.
b) The first plot shows that linearity is well maintained so linear assumption is fine.
No pattern observed in the second plot which indicates homoschedasticity assumption to be valid.
The points more or less fall on the Q-Q line which indicates the assumption of normality to be valid.
c) obviously second model with the transformed response should be recommended since all the assumptions are valid here.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.