1. Advanced Math Topics Chapter 11 Review

2. A magazine publisher has determined that the monthly circulation of the magazine depends upon the price charged per issue as shown below: Price per issue, x Circulation in thousands, y 1.0055 1.2549 1.5043 1.7539 2.0037 2.5030 Find: Σ x = Σ y = Σ x 2 = Σ y 2 = Σ xy = x = n = 10 253 18.125 11,065 398 1.6667 6

3. 1) C ompute the coefficient of correlation for this data. r = -0.9838

4. 2) I s r significant? The critical r from the back of the book for n = 6 and r 0.025 is + or -0.811. The computed R from the last slide is outside the region (closer to 1 or -1), so the correlation coefficient is significant.

5. 3) F ind the least-squares prediction equation. = -16.2286 = 69.2143 y = -16.2286x + 69.2143

6. 4) I f the magazine is priced to sell at $2.25, what is its predicted circulation? y = -16.2286(2.25) + 69.2143 y = 32.7000 which stands for 32,700 newspapers. If this number is used again, use 32.7000.

7. 5) W hat is the value of the standard error of the estimate? = 1.7864

8. 6) A t the 5% level of significance, does the data indicate that the price charged per issue can be used as a predictor of its circulation? Find the critical t and calculate t. t 0.025 with df = 4. The critical t-value is + or – 2.776. t = 10.9706 Since t is outside the interval, we reject that the slope is 0. Thus, the price is a predictor of circulation.

9. 7) F ind a 95% prediction interval for the circulation, in thousands, for the price per issue of $2.25. 26.8329 to 38.5671 thousand papers.

10. HW: Complete #1-7 on this Powerpoint on your own(link on School Loop or my webpage to Chapter 11 Review) OR do the following: P. 593 #5 r = ?, is r significant? LSR equation. Find y when x = 6 Find s e Can we use prediction line? Find 95% interval for y when x = 6