To earn full credit for this question, use your own sheet of paper to solve the problem, showing all steps of your work . A regression was run to determine if there is a relationship between the happiness index (y) and life expectancy in years of a given country (x). The results of the regression were: y=a+bx a=-1.278 b=0.103 (a) Write the equation of the Least Squares Regression line of the form y= (b) Which is a possible value for the correlation coefficient, r? 1.528 O-1.528 0 0.709 O-0.709 (c) If a country increases its life expectancy, the happiness index will increase decrease (d) If the life expectancy is increased by 0.5 years in a certain country, how much will the happiness index change? Round to two decimal places. (e) Use the regression line to predict the happiness index of a country with a life expectancy of 84 years. Round to two decimal places