A researcher is interested if the number of pets people own (the x-variable) is related to their stress on a scale of 0-80 (the y-variable). Given these sample data points:

	xn	yn
n1	2	60
n2	1	50
n3	3	40
n4	4	70
n5	4	50

Calculate and show all your work:

1. cov_xy(the covariance ofxand y)
2. s_x(the standard deviation ofx)
3. s_y(the standard deviation ofy)
4. r_xy(the correlation ofxand y

2. For the same data-set:

1. Calculate the regression prediction equation ( = bx + a).
2. Provide an interpretation for the slope (b) and the y-intercept (a).
3. If someone has three pets (x = 3), what would you predict their stress to be (the y-variable)?
4. If someone has eight pets (x = 8), what would you predict their stress to be (the y-variable)? Why might calculating this be a problem?