Please answer the question without Excel

Demand for stereo headphones and music players for joggers has caused Nina Industries to grow almost 50 percent over the past year. The number of joggers continues to expand, so Nina expects demand for headsets to also expand, because, as yet, no safety laws have been passed to prevent joggers from wearing them. Demand for the players for this year was as follows:

MONTH	DEMAND (UNITS)
January	4,250
February	4,350
March	4,050
April	4,450
May	5,050
June	4,750
July	5,350
August	4,950
September	5,450
October	5,740
November	6,345
December	6,045

Using linear regression analysis, what would you estimate demand to be for each month next year? Using a spreadsheet, follow the general format in Exhibit 3.7.

Note: Do not round intermediate calculations. Round your answers to 2 decimal places.

To be reasonably confident of meeting demand, Nina decides to use 3 standard errors of estimate for safety. How many additional units should be held to meet this level of confidence?

Note: Do not round intermediate calculations. Round your answer to the nearest whole number.