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 slope of the trend line is 15. What does that mean in regard to the data of the scatterplot? Check all that apply. The slope represents the rate of change of the data. Advertising costs increase $15,000 as sales increase by $1,000. Sales increase $15,000 as ads increase by $1,000. A positive slope infers a negative correlation. A positive slope infers a positive correlation.