Question

A graph titled Monthly Sales and Advertising Costs has Advertising Costs (1,000 dollars) on the x-axis and sales (1,000 dollars) on the y-axis. A line goes through points (6.4, 117) and (6.6, 120).
The scatterplot and trend line show a positive correlation between advertising costs and sales.

Which two points can be used to find the slope of the trend line?

Point 1:
Point 2:

Answer 1

To find the slope of the trend line, you can use the two points that are on the line. The points provided in your description are:

- Point 1: (6.4, 117)
- Point 2: (6.6, 120)

You would use these two points to calculate the slope of the trend line. The slope (m) can be calculated using the formula:

\[
m = \frac{y_2 - y_1}{x_2 - x_1}
\]

Substituting in the values from the points:

- \( (x_1, y_1) = (6.4, 117) \)
- \( (x_2, y_2) = (6.6, 120) \)

You can now calculate:

- \( y_2 - y_1 = 120 - 117 = 3 \)
- \( x_2 - x_1 = 6.6 - 6.4 = 0.2 \)

Thus, the slope is:

\[
m = \frac{3}{0.2} = 15
\]

So, the two points you can use to find the slope of the trend line are:

Point 1: (6.4, 117)
Point 2: (6.6, 120)