A study was made by a retail merchant to determine the relation between weekly advertisingexpenditures and sales. The following data were recorded:
Advertising
Costs ($) 40 20 25 20 30 50 40 20 50 40
Sales ($) 350 420 365 345 440 425 480 400 520 510
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.
d) Evaluate s2
e) construct a 99% confidence interval for á
f) construct a 99% confidence interval for beta.