David Ding advertises on a local radio station. For the past six week, the manager has kept records of the humber of minutes of advertising that were purchased, and the sales for that week. Week 1, 2 minutes of advertising with $1,400 in sales. Week 2, 1 minute, $920 in sales. Week 3, 3 minutes advertising, $1,100 in sales. Week 4, 5 minutes of advertising with $2,265 in sales. Week 5, 5 minutes of advertising, $2,8990 in sales. Week 6, 4 minutes in advertising, $2,200 in sales.
1. What is the y-intercept, the slope and the correlation coefficient from the above data
2. Estimate sales if 7 minutes of advertising were purchases.
3. Estimate sales if 8 minutes were purchases.
4. How many minutes of advertising should David buy to attain sales of $3,000?