Question

9) The number of adult Americans who smoke continues to drop. Here are estimates of the percents of adults (aged 18 and over) who were smokers in the years after 1965 (x = years since 1965). (this is only a small portion of the entire data set) Year (x) | Smokers (y) ---|--- 0 | 42.5 5 | 39.0 15 | 28.5 40 | 20.0 (a) Here are the means and standard deviations for the complete set of data and the correlation between percent of smokers and year: x? = 33.7 Sx = 12.9 y? = 26.1 Sy = 7.2 r = -0.97 Use this information to find the least-squares regression line (b) According to your regression line, how much did smoking decline per year during this period, on average? (c) What percent of the observed variation in percent of adults who smoke can be explained by change over time?

          9) The number of adult Americans who smoke continues to drop. Here are estimates of the percents of adults (aged 18 and over) who were smokers in the years after 1965 (x = years since 1965). (this is only a small portion of the entire data set)

Year (x) | Smokers (y)
---|---
0 | 42.5
5 | 39.0
15 | 28.5
40 | 20.0

(a) Here are the means and standard deviations for the complete set of data and the correlation between percent of smokers and year:
x? = 33.7
Sx = 12.9
y? = 26.1
Sy = 7.2
r = -0.97

Use this information to find the least-squares regression line

(b) According to your regression line, how much did smoking decline per year during this period, on average?

(c) What percent of the observed variation in percent of adults who smoke can be explained by change over time?

9) The number of adult Americans who smoke continues to drop. Here are estimates of the percents of adults (aged 18 and over) who were smokers in the years after 1965 (x = years since 1965). (this is only a small portion of the entire data set)

Year (x) | Smokers (y)
—|—
0 | 42.5
5 | 39.0
15 | 28.5
40 | 20.0

(a) Here are the means and standard deviations for the complete set of data and the correlation between percent of smokers and year:
x? = 33.7
Sx = 12.9
y? = 26.1
Sy = 7.2
r = -0.97

Use this information to find the least-squares regression line

(b) According to your regression line, how much did smoking decline per year during this period, on average?

(c) What percent of the observed variation in percent of adults who smoke can be explained by change over time?

Added by Joann B.

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