Why would cos 30° = cos -30°?

Given are five observations for two variables, x and y. xi 1 2 3 4 5 yi 3 7 5 11 14 which of the following is a scatter diagrams accurately represents the data? what does the scatter diagram developed in part (a) indicate about the relationship between the two variables? try to approximate the relationship betwen x and y by drawing a straight line through the data. which of the following is a scatter diagrams accurately represents the data? develop the estimated regression equation by computing the values of b 0 and b 1 using equations (14.6) and (14.7) (to 1 decimal). = + x use the estimated regression equation to predict the value of y when x = 4 (to 1 decimal). =