Predictive Modeling
Homework 4
预测建模代写 1.Linear Regression Data File Table 6.3 Carbohydrate diet.xls Please refer to Dobson Exercise 6.3 on page 119 and answer the following.
1.Linear Regression 预测建模代写
Data File Table 6.3 Carbohydrate diet.xls Please refer to Dobson Exercise 6.3 on page 119 and answer the following.
Consider the following two models
(a) Fit Model B and perform the following:
- Calculate the 95% confidence interval for β1, the coefficient for age.
- Test the hypothesis (at 5%) that the response does not depend on age.
(b) Fit Model A and calculate the 95% prediction interval when protein = 21.
(c) Compare Model A with Model B, use deviance to test the hypothesis (at 5%) that the response does not depend on age.
2. 预测建模代写
National Life Expentancies data for the following questions. this exercise involves data filename ”UNLifeExpectancy” from Frees page 137.
(This exercise continu the analysis begin in Exercises 1.7, 2.22, and 3.6) This is considering Health system from n = 185 countries. Use LIFEEXP as response variable. We are asking to anaylyze the following:
(a) Consider the regrssion using three explanatory variables, FERTILITY, PUBLICEDUCATION, and LNHEALTH. Test whether PUBLICEDUCATION and LNHEALTH are jointly statistically significant (it means that the coefficients of the two variables are equal to zero versus the alternative that not both the coefficients are zero), using the F-test. Stat your null and alternative hypothses, decision-making criterion, and decision-making rules. (hint use the coefficient of determination, R2 , form for calculaing the test statistic.) Provide an approximate p−value for the test.
(b) We now introduce the REGION variable, summarized in Table 4.11 (Frees, page 137), A box of plot of life expectancies versus REGION is given in Figure 4.8 (Frees, Page 138). Describe what we learn from the table and box plot about the effect of REGION on LIFEEXP.
(c) Fit a regression model using only the factor REGION. Is REGION a statistically significant determinant of LIFEEXP? State your null and alternative hypotheses, decision-making criterion, and decision making rules.
(d) Fit a regression model using three explanatory variables, FERTILITY, PUBLICEDUCATION, and LNHEALTH (the natural logarithmic transform of PRIVATE–HEALTH), as well as the categorical variable REGION.
- You are examining a country that is not in the sample with values FERTILITY = 2.0, PUBLICEDUCATION = 5.0, and LNHEALTH = 1.0, produce two predicted life expectancy values by assuming that the country is from (1) an Arab state and (2) sub-Saharan Africa.
- Provide a 95% confidence interval for the differentce in the life expectancies between an Arab state and sub-Saharan Africa.3. provide the (usual ordinary least squares) point estimate for the differentce in the life expectancies between a country from sub-Saharan Africa and a high-income OECD country.
