A candy bar manufacturer is interested in trying to estimate how sales are influenced by the price of their product. In order to do this, the company randomly chooses 6 small cities and offers the candy bar at different prices. Using candy bar sales as the dependent variable, the company will conduct a simple linear regression on the data below:

City Price$ Sales

RiverFalls 1.30 100

Hudson 1.60 90

Ellsworth 1.80 90

Prescott 2.00 40

Rock Elm 2.40 38

Stillwater 2.90 32

what is the estimated mean change in the sales of the candy bar if price goes up by $1.00?