Question

Use the normal equations to directly apply the least squares method (that is, do not use a transformation or Excel’s built in trendline function) to the given data for the indicated model. Compute D and dmax as bounds for cmax; what do these bounds suggest about improving the fit by using the Chebyshev criterion?

x 1 2 3 4 5

y 1 1 2 2 4

a. y = ax + b

b. y = ax2

Analyze the deviations for each model. Which model is a better fit? Support your conclusions

Answer 1

Calculation of Slope and Intercept using Excel SLOPE and INTERCEPT functions is following

Calculation of seasonal weights is as follows:

Seasonally adjusted forecast using trend line and seasonal weights and the error analysis is as follows