National Scan, Inc., sells ratio frequency inventory tags. Monthly sales for a 6-month period were as follows: Month: Sales Feb 48 Mar 45 Apr 41 May 41 Jun 39 Jul 36 Disregard the demand pattern of the given time series, You are asked to use the time series to derive a trend equation. In order to derive the trend equation is Ft = a + bt, you have to compute several components to compute the values for the variables a and b. Answer the following questions pertaining to information that are relevant to deriving the trend equation. a) The Σty = Blank 1 b) The Σy = Blank 2 c) The value for the b (slope of the trend line) = Blank 3 (in 3 decimal places) d) The value for the a (intercept of the trend line) = Blank 4 (in 3 decimal places)