Is there a way to remember that a closed circle on a graph is less than or equal to/ greater than or equal to and an open circle on a graph is just less than or equal to?

answer: your slope is /4

answer-

the sum of the residuals for all the points is 0

solution-

while doing a regression analysis our objective is to find a line of best fit. usually all the data points don’t lie exactly on this regression equation line. they are scattered around the line.

a residual represents the difference or variation between the actual or observed value and the predicted value. on the graph, it is the vertical distance between a data point and the regression line.

they are positive if they lie above the regression line and negative if they lie below the regression line. if the regression line actually passes through the point, the residual at that point is zero, i.e the observed value is same as the predicted value.

if the line is actually the line of best fit, then sum of the residuals and their mean is equal to zero.