Atrend forecast equation is being developed to describe sales over time. the analyst has completed the tabulation using the raw data and is about to develop the forecast equation with the least squares equations. use the calculated trend information tabled below to calculate the simple linear regression equation (hint: for y = a + bx, find the values of a and b). number of periods, n = 5 ybar = 5 xbar = 3 sum ( x2 ) = 55 sum ( xy ) = 80 the calculated linear regression equation is: