Given:
The scatter plot and trend line.
To find:
Type of association, slope, equation of trend line and average cost of apple per pound.
Solution:
Form the given graph it is clear that the trend line passes through the two points (0,0) and (12,24).
Slope of trend line is



Slope of trend line is positive. It means, it represents positive correlation.
So, the type of association of the scatter plot is positive association.
Therefore, the slope of trend line is 2.
The trend line passes through (0,0) have slope 2, so the equation of the trend line is



Therefore, the equation of trend line is
.
Slope of the line is 2.
Therefore, the average cost of apples per pound is $2.
∠ADC = 112°
∠ADC =6x + 7 + 12x - 3
Equate both:
6x + 7 + 12x - 3 = 112
Solve for x :
6x + 7 + 12x - 3 = 112
Combine like terms:
18x + 4= 112
Take away 4 from both sides:
18x = 108
Divide both sides by 18:
x = 6
Find ∠ADB:
6x + 7 = 6(6) + 7 = 43
Answer: ∠ADB = 43°
Solve this equation:
300+5x=450+2x
3x = 150
x = 50
so the answer is 50 books