Based on data from L Brown Vital Signs 2003 The Environmenta

Based on data from L Brown, Vital Signs 2003: The Environmental Trends that are Shaping our Future, the following chart of cigarette smoking data has been prepared. The line of best fit, the regression line, is y = -8.6893x + 18, 303. where x = year and y = average number of cigarettes smoked per person, world-wide The value of r^2 is 0.8978. Use the regression line to estimate the average number of cigarettes smoked per person in 1988, to the nearest integer Show some work. Use the regression line to estimate the average number of cigarettes smoked per person in 2001, to the nearest integer Show some work In what year (to the nearest year) does the regression line estimate an average number of cigarettes smoked per person of 880cigarettes per person? Show- work, solving an appropriate equation. What is the slope of the regression line and what are the units of measurement? In a sentence, interpret what the slope is telling us, in the context of this real-world application. What is the value of the correlation coefficient, r? Also, interpret its value looking at the graph and the size of r. do you judge the strength of the linear relationship to be very strong, moderately strong, somewhat weak, or very weak?

Solution

y = -8.6893x+ 18303

a) x= 1988 ; find y : y = -8.689*1988 +18303 = 1029.268 = 1029 cigrattes

b) x = 2001 , find y , : y = -8.689*2001 +18303 = 916.31 = 916 cigrattes

c) No. of cigrattes = 880 per person

880 = -8.689x +18303

x = 2005.17 = 2005 year

d) Slope of regression equation is -8.6893

Units of slope is avg no. of cigrattesper person per year

In real world a negative slope of nidcates that avg no. of cigrattes smoked by per person is decearing with every passing year.