The movie Harry Potter and the Sorcerer€™s Stone opened as a great success. But every movie sees declining revenue over time. Here are the daily revenues for the movie during its first 17 days.

a) Without plotting the data, what components can you see in this series? Be specific. For some series, a €œseasonal€ effect repeats weekly rather than annually. Here€™s a regression model fit to these data with dummy variables for days of the week. (Day# counts days starting at 1.)

b) Interpret the coefficient of Day#.
c) Interpret the coefficient of Saturday in this model.
d) Predict what earnings probably were for Monday 12/3/01. What does this say about the model?
e) What probably happened to earnings after the initial 17 days?

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Date Eamings (SM) 11/16/01 11/17/01 11/18/01 11/19/01 11/20/01 Day Friday Saturday Sunday Monday Tuesday Wednesday 11/21/01 Thursday 11/22/01 Friday Saturday Sunday Monday Tuesday Wednesday 11/28/01 Thursday Friday Saturday Sunday 11/23/01 11/24/01 11/25/01 11/26/01 1/27/01 11/29/01 11/30/01 12/1/01 12/2/01 Dependent variable is: Earnings R squared., 96.9% R squared (adjusted ).. 94.6% s = 2.365 with 17-8=9 degrees of freedom Variable Coeff Intercept 21.0000 2.090 Day# Friday 12.4286 2.179 SE(Coeff) t-ratio P-value 10.0 <0.0001 -12.0 <0.0001 5.70 0.0003 0.0003 0.0051 0.1068 -0.992 0.3473 -0.392 0.7041 1.425 0.1194 aturday 12.5238 2.166 5.78 3.69 Sunday Monday Tuesday 2.35714 2.377 Wednesday 0.928571 2.369 7.95238 2.160 -4.2857 2.392