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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= -0.345

b=0.114

(a) Write the equation of the Least Squares Regression line of the form

y^=_____+______x

(b) Which is a possible value for the correlation coefficient,r?

• 0.717
• -0.717
• 1.381
• -1.381

(c) If a country increases its life expectancy, the happiness index will

• increase
• decrease

(d) If the life expectancy is increased by 2.5 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 83 years. Round to two decimal places.

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