Read the dataset using r program, and calculate average, stand deviation, and median for each variables. 2. perform a regression for y = ax + bz + c, and what are the estimators of a, b and c obtained from the regression results? 3. find the 95% confidence intervals for a and b. 4. based on the question 3, can the model be reduced to y = ax + c? why? 5. now perform a new regression for y = ax + c, generate a scatter plot of (x, y) and a fitted regressoin curse. 6. based on question 5, is the model y = ax+c enough to describ the relation between x and y? 7. try to improve the model in question 6.