Advanced Math Topics Chapter 11 Review

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 Find: Σ x = Σ y = Σ x 2 = Σ y 2 = Σ xy = x = n = ,

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

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

3) F ind the least-squares prediction equation. = = y = x

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

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

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 with df = 4. The critical t-value is + or – t = Since t is outside the interval, we reject that the slope is 0. Thus, the price is a predictor of circulation.

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

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