Question

Demand for stereo headphones and MP3 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 last year was as follows:

MONTH	DEMAND (UNITS)
January	4,210
February	4,310
March	4,010
April	4,410
May	5,010
June	4,710
July	5,310
August	4,910
September	5,410
October	5,710
November	6,310
December	6,010

a. 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. (Do not round intermediate calculations. Round your answers to 2 decimal places.)

Month	Forecast
January
February
March
April
May
June
July
August
September
October
November
December

b. To be reasonably confident of meeting demand, Nina decides to use 4 standard errors of estimate for safety. How many additional units should be held to meet this level of confidence? (Do not round intermediate calculations. Round your answer to the nearest whole number.)

Additional units            

Q2)

Demand for stereo headphones and MP3 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 last year was as follows:

MONTH	DEMAND (UNITS)
January	4,210
February	4,310
March	4,010
April	4,410
May	5,010
June	4,710
July	5,310
August	4,910
September	5,410
October	5,710
November	6,310
December	6,010

a. 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. (Do not round intermediate calculations. Round your answers to 2 decimal places.)

Month	Forecast
January
February
March
April
May
June
July
August
September
October
November
December

b. To be reasonably confident of meeting demand, Nina decides to use 4 standard errors of estimate for safety. How many additional units should be held to meet this level of confidence? (Do not round intermediate calculations. Round your answer to the nearest whole number.)

Additional units            

Answer 1

Using linear regression analysis,

The results obtained are

Best-fit values

Slope 192.3 ± 22.57

Y-intercept3777 ± 166.1

X-intercept-19.64

1/Slope0.0052

95% Confidence Intervals

Slope142.0 to 242.6

Y-intercept3407 to 4147

X-intercept-28.95 to -14.16

Goodness of Fit

R square0.8790

Sy.x269.9

Is slope significantly non-zero?

F 72.62

DFn,DFd 1,10

P Value< 0.0001

Deviation from horizontal? Significant

Data

Number of XY pairs 12

Equation Y = 192.3*X + 3777 . we use this equation to calculate the future values. For January we take x= in the continuum as 13, February as 14 and so on

The table thus obtained is as follows

Month(Next year)	Forecast
Jan	6276.9
Feb	6469.2
Mar	6661.5
Apr	6853.8
May	7046.1
June	7238.4
July	7430.7
Aug	7623
Sept	7815.3
Oct	8007.6
Nov	8199.9
Dec	8392.2