For part c. my initial answer was b = 2.69 and a = 58.58, both are incorrect. I used the regression formula, as excel wasn't said to be used.

Please explain in full detail.

Historical demand for a product is as follows: DEMAND April 63 May 58 June 73 July 63 August 78 September 73 a. Using a simple four-month moving average, calculate a forecast for October. (Round your answer to 2 decimal places.) Forecast for October 71.75 b. Using single exponential smoothing with a = 0.30 and a September forecast = 65, calculate a forecast for October. (Round your answer to 2 decimal places.) Forecast for October 67.40c. Using simple linear regression, calculate the trend line for the historical data. Say the Xaxis is April =1, May = 2, and so on, while the Yaxis is demand. (Round your intercept value to the nearest whole number and slope value to 2 decimal places.) _I--- d. Calculate a forecast for October using your regression formula. (Round your answer to 2 decimal places.) Forecast for October