A study was made by a retail merchant to determine the relation between weekly advertising expenditures and sales.
Advertising Costs ($) Sales ($)
40 385
20 400
25 395
20 365
30 475
50 440
40 490
20 420
50 560
40 525
25 480
50 510
(a) Plot a scatter diagram.
(b) Find the equation of the regression line to predict weekly sales from advertising expenditures.
(c) Estimate the weekly sales when advertising costs are $35