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). yy^=a+bx a=-1.218 b=0.171 (b) Which is a possible value for the correlation coefficient, r? (c) If a country increases its life expectancy, the happiness index will increase or decrease ? (d) If the life expectancy is increased by 5 years in a certain country, how much will the happiness index change? Round

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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).

yy^=a+bx
a=-1.218
b=0.171

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

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

increase or decrease ?

(d) If the life expectancy is increased by 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 59 years. Round to two decimal places.

 

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As per the guidelines, we are only allowed to solve three subparts, please post the other questions as a different question.

The general form of the regression line is:

Y^=a+bX

Where ′Y^ is the predicted value, 'a' is the intercept, 'b' is the slope of the line and 'X' is the independent variable.

In this case, the regression line is given as:

Y^=-1.218+0.171 X

The slope of this equation is 0.171. 

Since the slope of the regression line is positive, thus if the value of X increases, the value of Y^ increases. Therefore, it can be concluded that for every one-unit increase in x, there is a 0.171  increase in y.

(a)

Y^=-1.218+0.171 X

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