Question

finding the slope of the trend line
the scatterplot and trend line show a positive
correlation between advertising costs and sales.
using the points (6.4, 117) and (6.6, 120), what is the
slope of the trend line?
○ -15
○ -12
○ 12
○ 15

Explanation:

Step1: Recall the slope formula

The slope formula is \(m=\frac{y_2 - y_1}{x_2 - x_1}\). Let \((x_1,y_1)=(6.4,117)\) and \((x_2,y_2)=(6.6,120)\).

Step2: Substitute the values into the formula

\(m=\frac{120 - 117}{6.6 - 6.4}\)
\(m=\frac{3}{0.2}\)

Step3: Calculate the value

\(m = 15\)

Answer:

15 (the fourth option)