Explain why the slope b of the least-squares line always has the same sign (positive or negative) as the sample correlation coefficient r. Choose the correct relationship between b and r, where sx and sy are the standard deviations of the x values and the y values, respectively. a. b = 1/r(sx/sy)
b. b = r(sy/sx)
c. b = 1/r(sy/sx)
d. b = r(sx/sy)

You are in charge of the customer service phone line with many employees. at the end of each phone callthe customers are asked to rate their service from 1 to 5 stars, with 5 being the best. you find the averagerating for 20 randomly selected employees and decide you want to improve the ratings so you require thoseemployees to go through a new training program. you then wait a week and find the new average rating foreach employee. the average change is an increase in 1.3 stars with a standard devation of .9 stars.(a) is this data paired or not paired? (b) what are the null and alternative hypothesis being tested? (c) what is the t-statistic you would use? write the general formula and the final calculation.(d) sketch a t-distribution, label your t-statistic and the probability you would be interested in: