In a scatterplot, let K denote the least-squares regression line computed with outlier A included and let L denote the least-squares regression line computed without outlier A. Which of the following must be true about the slopes of K and L?
a) Both slopes are positive, and the slope of K is less than the slope of L. b) Both slopes are positive, and the slope of K is greater than the slope of L. c) The slope of K is negative, and the slope of L is positive. d) The two slopes are equal.
I encountered this statistics problem in a recent test and though I have already taken statistics 1 I was not familiar with this problem. I guessed choice a and I wonder if that is the correct answer. Those any one knows the answer to this problem. Thank you.